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It involves the scientific study of the structure,
properties, composition, reactions, andpreparation (by synthesis or by other means) of
carbon-based compounds, hydrocarbons, and
their derivatives.
ORGANIC CHEMISTRY
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an organic compound consisting entirely of
hydrogen and carbon.
HYDROCARBON
Sigma bond
A single bond
CxHx
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Saturated hydrocarbons (alkanes or paraffins) are the
simplest of the hydrocarbon species and are composed
entirely of single bonds and are saturated with
hydrogen.
Unsaturated hydrocarbons have one or more double or
triple bonds (pi bond) between carbon atoms. Alkenes (olefins) has a double bond
Alkyne has a triple bond
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Naming of Hydrocarbon
CnH2n+2 CnH2n CnH2n-2
n ALKANE ALKENE ALKYNE
1 METHane _______ _______
2 ETHane ETHene ETHyne
3 PROPane PROPene PROPyne
4 BUTane BUTene BUTyne
5, 6 so on PENTane,
HEXane so on
PENTene,
HEXene so on
PENTyne,
HEXyne so on
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Introduction to Thermodynamics
Thermodynamics
is the scientific study of the interconversion ofheat and other kinds of energy.
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The Nature of Energy
Energy
-is usually defined as the capacity to do work.
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The Nature of Energy
Work
-directed energy change resulting from a process.
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Types of Energy
Radiant energy
comes from the sun and isearths primary energy source.
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Chemical Energy
Thermal energy
is the energy associated with therandom motion of atoms and molecules.
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Types of Energy
Chemical Energy
is stored within the structuralunits of chemical substances.
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Types of Energy
Potential Energy
is energy available by virtue of anobjects position.
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Types of Energy
Kinetic Energy
the energy produced by amoving object.
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Law of Conservation of Energy
Energy can neither be created nor destroyed butit can be transformed from one form to another.
the total quantity of energy in the universe isassumed constant.
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Energy Changes in Chemical Reactions
Heat
is the transfer of thermal energy between twobodies that are at different temperatures
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Energy Changes in Chemical Reactions
Surroundings
are the rest of the universe outside the system.
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Energy Changes in Chemical Reactions
Systems
usually include substance involved in chemicaland physical changes.
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3 types of systems
Open system
Closed system
Isolated system
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Open system
can exchange mass and energy, usually in the form of heat withits surroundings.
Isolated system
does not allow the transfer of either mass or energy.
Closed system
allows the transfer of energy (heat) but not mass.
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Exothermic process
any process that gives off heat-that is, transfers
thermal energy to the surroundings.
Endothermic process
in which heat has to be supplied to the system.
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Change of Internal Energy
E=Ef-Ei
Ef-internal energies of the system in thefinalstates respectively.
Ei-internal energies of the system in theinitialstates respectively.
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The internal energy of a system has two
components:
Kinetic energy
Potential Energy
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Work and Heat
Work
done by the gas on the surroundings.
W=-P
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Work
V= the change in volume is given byVf-Vi
1L.atm = 101.3 J
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Enthalpy of Chemical Reactions
Enthalpy
H=E+PV
H=enthalpy
E=is a internal energy of the systemP=pressure of the system
V=volume of the system
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Enthalpy of Chemical Reactions
Enthalpy of Reactions
The difference between the enthalpies of theproducts and the enthalpies of the reactants.
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Enthalpy of Chemical Reactions
Thermochemical Equations
H=6.01 kJ/mol
The per mole in the unit forHmeans that thisisthe enthalpy change per mole of the reaction
(or process) as it is written.
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Enthalpy of Chemical Reactions
A Comparison ofHandE
E=H-PV
E=H-RTn
n=number of moles of product gases-number ofmoles of reactant gases
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Standard Enthalpy of Formation and
Reaction
Standard Enthalpy of Formation (Hf)
the sea level reference point for all enthalpyexpressions.
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Standard Enthalpy of Formation and
Reaction
Standard Enthalpy of Reaction(H rxn)
The enthalpy of a reaction carried out at 1 atm.
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Calorimetry
The measurement of heat changes.
Calorimeter-a device that measured the
heat changes in physical andchemical processes.
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Constant-Volume
refers to the volume of the container whichdoest not change during the reaction.
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Calorimetry
Constant-Volume Calorimetry
heat of combustion is usually measured byplacing a known mass of a compound in asteel container.
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Calorimetry
Constant-Pressure Calorimetry
which is used to determine the heat changes fornoncombustion reactions.
1 cal=4.184J
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THERMOCHEMISTRY
is the study of heatchange in chemical
reactions.
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Heat
heat is not a state function.
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Specific Heat and Heat Capacity
Specific heat(s)-is the amount of heat required
to raise the temperature of 1 gram pf thesubstance by 1 degree Celsius.
Heat Capacity (C)- is the amount of heat
required to raise the temperature of a given
quantity of the substance by 1 degree Celsius.
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Heat Capacity
C=ms