CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.
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Transcript of CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.
![Page 1: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/1.jpg)
CHEMISTRY SEMESTER REVIEW
LAST CALL FOR QUESTIONS
Do you remember how to identify the type of reaction
bull 2 H2O rarr 2 H2 + O2
ndash What type of reaction is this
Decomposition Reaction
bull C10H8 + 12 O2 rarr 10 CO2 + 4 H2O
ndash What type of reaction is this
Combustion Reaction
GRAMS to MOLECULES
bull How many molecules are there in 250g of NH3
bull What do we do first
bull First thing to do is find the molar mass of the compound Molar mass is the sum total of every atomrsquos mass in the compound
Whats the molar mass of NH3NITROGEN(N) = 1401gmolHYDROGEN(H) = 1008gmol
Whats the molar mass of NH3
bull N = 1401 g
bull H = 1008 g (times 3 because there are three hydrogen atoms in NH3)
bull The molar mass is 17034 gmole (or 17034 grams per 1 mole of NH3)
Next Step (250g of NH3)
bull Next once you know the total mass of your substance you can convert to moles by dividing the total mass of NH3 (250 g) by the molar mass (17034 gmol)
250 g 1 mol (of NH3)
17034 g1468 mol =
Finally the number of molecules can be calculated
To do this you must convert moles to molecules using Avogadrorsquos which is
602 X 1023
1468 mol602 x 1023
molecules
1 mol8837 x 1024 =
molecules
TYPES OF SYSTEMS
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 2: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/2.jpg)
Do you remember how to identify the type of reaction
bull 2 H2O rarr 2 H2 + O2
ndash What type of reaction is this
Decomposition Reaction
bull C10H8 + 12 O2 rarr 10 CO2 + 4 H2O
ndash What type of reaction is this
Combustion Reaction
GRAMS to MOLECULES
bull How many molecules are there in 250g of NH3
bull What do we do first
bull First thing to do is find the molar mass of the compound Molar mass is the sum total of every atomrsquos mass in the compound
Whats the molar mass of NH3NITROGEN(N) = 1401gmolHYDROGEN(H) = 1008gmol
Whats the molar mass of NH3
bull N = 1401 g
bull H = 1008 g (times 3 because there are three hydrogen atoms in NH3)
bull The molar mass is 17034 gmole (or 17034 grams per 1 mole of NH3)
Next Step (250g of NH3)
bull Next once you know the total mass of your substance you can convert to moles by dividing the total mass of NH3 (250 g) by the molar mass (17034 gmol)
250 g 1 mol (of NH3)
17034 g1468 mol =
Finally the number of molecules can be calculated
To do this you must convert moles to molecules using Avogadrorsquos which is
602 X 1023
1468 mol602 x 1023
molecules
1 mol8837 x 1024 =
molecules
TYPES OF SYSTEMS
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 3: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/3.jpg)
GRAMS to MOLECULES
bull How many molecules are there in 250g of NH3
bull What do we do first
bull First thing to do is find the molar mass of the compound Molar mass is the sum total of every atomrsquos mass in the compound
Whats the molar mass of NH3NITROGEN(N) = 1401gmolHYDROGEN(H) = 1008gmol
Whats the molar mass of NH3
bull N = 1401 g
bull H = 1008 g (times 3 because there are three hydrogen atoms in NH3)
bull The molar mass is 17034 gmole (or 17034 grams per 1 mole of NH3)
Next Step (250g of NH3)
bull Next once you know the total mass of your substance you can convert to moles by dividing the total mass of NH3 (250 g) by the molar mass (17034 gmol)
250 g 1 mol (of NH3)
17034 g1468 mol =
Finally the number of molecules can be calculated
To do this you must convert moles to molecules using Avogadrorsquos which is
602 X 1023
1468 mol602 x 1023
molecules
1 mol8837 x 1024 =
molecules
TYPES OF SYSTEMS
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 4: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/4.jpg)
Whats the molar mass of NH3NITROGEN(N) = 1401gmolHYDROGEN(H) = 1008gmol
Whats the molar mass of NH3
bull N = 1401 g
bull H = 1008 g (times 3 because there are three hydrogen atoms in NH3)
bull The molar mass is 17034 gmole (or 17034 grams per 1 mole of NH3)
Next Step (250g of NH3)
bull Next once you know the total mass of your substance you can convert to moles by dividing the total mass of NH3 (250 g) by the molar mass (17034 gmol)
250 g 1 mol (of NH3)
17034 g1468 mol =
Finally the number of molecules can be calculated
To do this you must convert moles to molecules using Avogadrorsquos which is
602 X 1023
1468 mol602 x 1023
molecules
1 mol8837 x 1024 =
molecules
TYPES OF SYSTEMS
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 5: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/5.jpg)
Whats the molar mass of NH3
bull N = 1401 g
bull H = 1008 g (times 3 because there are three hydrogen atoms in NH3)
bull The molar mass is 17034 gmole (or 17034 grams per 1 mole of NH3)
Next Step (250g of NH3)
bull Next once you know the total mass of your substance you can convert to moles by dividing the total mass of NH3 (250 g) by the molar mass (17034 gmol)
250 g 1 mol (of NH3)
17034 g1468 mol =
Finally the number of molecules can be calculated
To do this you must convert moles to molecules using Avogadrorsquos which is
602 X 1023
1468 mol602 x 1023
molecules
1 mol8837 x 1024 =
molecules
TYPES OF SYSTEMS
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 6: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/6.jpg)
Next Step (250g of NH3)
bull Next once you know the total mass of your substance you can convert to moles by dividing the total mass of NH3 (250 g) by the molar mass (17034 gmol)
250 g 1 mol (of NH3)
17034 g1468 mol =
Finally the number of molecules can be calculated
To do this you must convert moles to molecules using Avogadrorsquos which is
602 X 1023
1468 mol602 x 1023
molecules
1 mol8837 x 1024 =
molecules
TYPES OF SYSTEMS
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 7: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/7.jpg)
Finally the number of molecules can be calculated
To do this you must convert moles to molecules using Avogadrorsquos which is
602 X 1023
1468 mol602 x 1023
molecules
1 mol8837 x 1024 =
molecules
TYPES OF SYSTEMS
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 8: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/8.jpg)
TYPES OF SYSTEMS
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 9: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/9.jpg)
bull open systems can exchange mass and energybull closed systems allow the transfer of energy (he
at) but not massbull isolated systems do not allow transfer of either
mass or energy
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 10: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/10.jpg)
HYDROGEN EXPLOSION - combustion
bull Is this reaction taking place in an open closed or isolated system
bull the reacting mixture is the system (hydrogen oxygen and water molecules) everything else is the surroundings
bull This is exothermic because it is a combustion reaction (thermal energy leaves during this and all other exothermic reaction -- a lot of thermal energy is released in this example )
)(2)(2 222 lOHOgH
open system
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 11: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/11.jpg)
Whats an example of an isolated system
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 12: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/12.jpg)
Calorimetry - the measurement of heat changebull a calorimeter is an insulate
d closed container that creates an ISOLATED SYSTEM
bull a specific quantity of water surrounds a system carrying out a reaction
bull during the reaction heat leaves the inner container and is absorbed by the surrounding water
bull by recording temperature change the heat generated by a reaction can be calculated
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 13: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/13.jpg)
bull Heat Capacity ndash heat needed to raise a certain quanity of a su
bstance 1 degree (celsius)
bull Specific Heat ndash the heat needed to raise a 1 gram of a specifi
c substance 1 degree (celsius)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 14: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/14.jpg)
If volume and pressure remain constant then q = Hbull Either heat capacity or specific heat must be a
pplied to find a substances change in heatbull Remember
heat capacity specific heat
Δt x (C) = m x (s) x Δt
tmsqtCq
cc
J
g
J g
degCdegC
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 15: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/15.jpg)
Practice Questionbull A quantity of 1435 g naphthalene (C10H8) is bur
ned in a calorimeter The water temp rises from 2028 to 2595 degrees celsius If the heat capacity (C) is 1017 kJcelsius calculate the molar heat combustion of C10H8
bull What is being asked herebull How much heat per mole of napthalene is released into the calorime
ter
To do thisbull You need to figure out how much heat is generated by the
combustionbull You need to convert this total heat to q per mole (kJmol)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 16: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/16.jpg)
solving this problem
kJq
q
qqq
kJq
CCCkJq
tcq
rxn
rxncal
sys
syscalrxn
cal
cal
calcal
6657
0
6657
)28209525)(1710(
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 17: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/17.jpg)
We are not done
bull The question asks us to calculate the molar heat of combustion
bull So you have to find the molar mass of naphthalene (C10H8) have to use periodic table
bull molar mass of C10H8 is 1282 g
bull now we can convert from kJ1435 g to kJmol
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 18: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/18.jpg)
How to convert
kJmol 101515
mol 1
2128
4351
5766kJ-
3
810
810
810
combustion ofheat molar
x
HC
HCgx
HCg
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 19: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/19.jpg)
INTENSIVE and EXTENSIVE PROPERTIES
bull Extensive Properties - are properties that depend on how much matter is being consideredndash for example volume
bull the property of space a substance takes up is a value dependent on how much of the substance there is
ndash Can you think of others
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 20: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/20.jpg)
INTENSIVE and EXTENSIVE PROPERTIES
bull Intensive Properties - properties that do NOT depend on how much matter is being consideredndash for example boiling point
bull the boiling point of liquid water into water vapor is the same regardless of how much water there is
ndash can you think of others
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 21: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/21.jpg)
MOLE vs MOLARITY
bull mole (mol)bull 1 mol = 602 x 10^23
particles of a particular substance
bull molarity (M)bull molarity or molar co
ncentration is the number of moles of solute per liter of solutionthe dissolved
substanceA solvent is what a solute dissolves in to make a solution
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 22: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/22.jpg)
molarity is defined as
molarity = moles of solute liters of solution
So is molarity an intensive or extensive property
intensive property
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 23: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/23.jpg)
Change in Enthalpy of a Reaction
rxnH
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 24: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/24.jpg)
Standard Enthalpy of Formation
bull DEFINITIONndash the enthalpy of a reaction carried out at 1 atm and at 25 degr
ees Cndash the enthalpy value relates to the heat absorbed or released
during the formation of 1 mole of a specific compound
The symbol for this value is represented as
formation ofenthalpy Standared fH
Once we know these values we can calculate the change in enthalpy of a reaction or
rxnH
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 25: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/25.jpg)
Standard Enthalpy of a Reaction rxnH
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
bull n = the coefficient of the productsbull m = the coefficient of the reactantsbull Σ = the sum ofbull f = formation bull deg = standard state conditions (1 atm and 25 degrees C)
m
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 26: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/26.jpg)
The most stable forms of substances will = 0
EXAMPLEGiven the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJ
calculate ΔH for the following reaction 32 O2(g) rarr O3(g)REMEMBER
)reactants()products(H
isequation dgeneralize The
fHfH nnrxn
O2 is the most stable form of oxygen So it is equal to 0
Therefore the the change in enthalpy is all about the product
(x products) - (0 reactants) = rxnH = X products = +2844 kJYou can check using the table on P 247
i
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 27: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/27.jpg)
P 247bull The ΔHdegf for O3(g) is +1422 bull The ΔHdegf for O2(g) is 0Given the equation 3 O2(g)rarr2 O3(g) ΔH = +2844 kJThere are two O3 in the equation (1422 kJ x 2 = 2844 kJ)
ndash we must remember the coefficientsbull Then the question asks us to calculate ΔH for the
following reaction 32 O2(g) rarr O3(g) bull There is only one O3
bull Since 32 O2(g) rarr O3(g) is frac12 of 3 O2(g)rarr2 O3(g) the enthalpy of the reaction will be frac12 as well
frac12 (+2844kJ)or +1422kJ
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 28: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/28.jpg)
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used
in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP IWRITE THE BALANCED EQUATIONTo carry any combustion reaction you need oxygen as a reactant Liquid water will always be included as one of the products
__ C4H4S(l) + ___ O2(g) rarr __ CO2(g) + ___ S02(g) + ___ H20(l)1 6 4 1 2
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 29: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/29.jpg)
Change of Enthalpy of Reaction
bull The combustion of thiophene C4H4S(l) a compound used in the manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
USE THE COEFFICIENTS FROM YOUR BALANCED EQUATION TO DETERMINE THE TOTAL CHANGE IN ENTHALPY IN THE FORMATION OF EVERY SUBSTANCE USED IN THE REACTION USE THIS INFORMATION TO WRITE YOUR ΔHdegRXN EQUATION
i
)reactants()products(H fHfH nnrxn
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 30: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/30.jpg)
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
PRODUCTS
4 (________kJmol CO2(g))2 (________kJmol H2O(l))1 (________kJmol SO2(g))
REACTANTS
X kJmol C4H4S(l)
6 (________kJmol O2(g))
-3935
-2858-2968 000
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 31: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/31.jpg)
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP II
i
[4(-3935) + 1(-2968) + 2(-2858)] ndash [1(ΔH) + 6(0)] = -2523
PRODUCTS -
REACTANTS = ΔHRXN
Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
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Change of Enthalpy of Reaction bull The combustion of thiophene C4H4S(l) a compound used in the
manufacture of pharmaceuticals produces carbon dioxide and sulfur dioxide gases and liquid water The enthalpy change in the combustion of one mole of C4H4S(l) is -2523kJ Use this information and data from Table 64 (p247) to establish ΔHdegf for C4H4S(l)
STEP III
SOLVE for X
i
-24424 - ΔH(reactants) = -2523
ΔHC4H4S(l) = 813kJmol
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 33: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/33.jpg)
CHANGE IN H
0H EXOTHERMIC
0H CENDOTHERMI
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 34: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/34.jpg)
Change in Enthalpy in a multi-step reaction
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 35: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/35.jpg)
Change in Enthalpy in a multi-step reaction
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 36: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/36.jpg)
CHEMICAL EQUILIBRIA
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 37: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/37.jpg)
Things to remember
This is how you convert an Equilibrium constant from Kc to Kp
Kp = Kc (00821 T)^Δn
Δn is the sum of all stoichiometric coefficients belonging to products minus the sum of all stoichiometric coefficients belonging to reactants
T is the temperature during the reaction in Kelvin Remember that Kelvin has exactly the same degree of difference between integers as celsius but it does have a different starting point Kelvins zero is 273deg less than celsius For example 2deg C is equal to 275deg K 27deg C is equal to 300deg K
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 38: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/38.jpg)
Qc and Kc Questionh
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 39: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/39.jpg)
EQUILIBRIUM of 2 or more RXNs
If a reaction can be expressed as the sum of two or more reactions the equilibrium constant for the overall reaction is given by the product of the equilibrium of the individual reactions
Kc = (Kc) (Kc)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 40: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/40.jpg)
Let me elaborate
nn
nn
c BA
DCK
][][
][][ nn
nn
c DC
FEK
][][
][][
c
c
c
K
__________________
K
K
FEBA
FEDC
DCBA
1st Step Reaction 2nd Step Reaction
OverallReaction
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 41: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/41.jpg)
To find the overall equilibrium of a multi-step reaction
cnn
nn
nn
nn
cc KDC
FEx
BA
DCKK
][][
][][
][][
][][
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
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![Page 42: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/42.jpg)
2 step reaction1st step reaction
N2(g) + O2(g) harr 2 NO(g) Kc1 = 23 x 10^-19
2nd step reaction
2 NO(g) + O2(g) harr 2 NO2(g) Kc2 = 3 x 10^6
Kc = Kc1 x Kc2 = (23 x 10^-19)(3 x 10^6) Kc = 7 x 10^-13
Write the equilibrium equation for this multi-step reaction
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
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- Slide 31
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- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 43: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/43.jpg)
CHEMICAL KINETICS
Reaction rates
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
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- Slide 27
- Slide 28
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- Slide 31
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- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 44: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/44.jpg)
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0074 Ms
a) At what rate is ammonia being formedb) At what rate is molecular nitrogen reacting
t
NH
t
H
t
N
322
2
1
3
1
1
1
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 45: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/45.jpg)
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is ammonia being formed s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
t
NH
t
NH
t
H
sM
3
32
2
10740
3
1
2
1
3
1t
NHsM
30740
3
2
_
-
_
t
NHsM
30490
GIVEN
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 46: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/46.jpg)
N2 + 3H2 rarr 2NH3Molecular hydrogen reacts at a rate of 0074 Ms
bull At what rate is molecular nitrogen reacting s
M
t
H07402
t
NH
t
H
t
N
322
2
1
3
1
1
1
-
GIVEN
t
N
t
N
t
H
sM
2
22
1
10740
3
1
1
1
3
1
t
NsM
20740)1(
3
1
t
NsM
20250
-
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
- Slide 51
-
![Page 47: CHEMISTRY SEMESTER REVIEW LAST CALL FOR QUESTIONS.](https://reader037.fdocuments.us/reader037/viewer/2022110323/56649d825503460f94a680a4/html5/thumbnails/47.jpg)
Describe the difference between Heat of solution and Heat of dilution Give an example of
each one
Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- Slide 39
- Slide 40
- Slide 41
- Slide 42
- Slide 43
- Slide 44
- Slide 45
- Slide 46
- Slide 47
- Slide 48
- Slide 49
- Slide 50
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Heat of solution is the amount of heat absorbed or released during the act of combining a solute with a solvent An example is adding salt to water There are two steps to this process the Lattice Energy (breaking down the molecules) and the heat of hydration (where the ionically charged particles dissolve by attracting to the dipole water molecules
Heat of dilution refers to the amount of heat absorbed or released when water is added to a solution already made In this latter case if the act of making a solution is exothermic adding more water will make it even more exothermic (hotter) For example as you add more and more water to a solution of sulfuric acid and water the more heat it releases (the more it burns)
Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
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Neutralization
bull Explain how you would neutralize an acid and a base
Mix an acidic solution with a basic solution wherein the ratio of H+ ions to OH- ions eq
ual to 1
Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
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Cabbage Juice as a pH indicator
bull Explain how cabbage juice works as a pH indicator There is anthocyanin in cabbage juice Anthocyanin reacts w
ith hydroxyl ions (OH-) Hydroxyl ions jump off anthocyanin when in an acidic solution thereby changing the chemical composition of the anthocyanin (the pH indicator) This will cause the juice to react with light differently than if these OH- ions had not jumped off the anthocyanin (makes the juice turn a reddish color) Conversely Hydroxyl ions will jump from the solution onto the anthrocyanin molecules when there is an excess of them in the solution (such as when cabbage juice is mixed with a basic solution) This causes the juice
(the pH indicator) to turn a yellowish color
NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
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NOT mentioned
bull Balancing redox reactions
bull Kw
bull Ka
bull Kb
bull pH
bull the galvanic cell
bullKNOW THESE CONCEPTS
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