Name: Date: Period: CBA REVIEW (Nuclear Chem. Mole Conversions, & Stoichiometry ... · ·...

Name:_______________________________________________ Date:__________________________Period:_________ CBA REVIEW (Nuclear Chem. Mole Conversions, & Stoichiometry)

NUCLEAR CHEMISTRY:

Complete the following table:

Alpha Beta Gama

Charge

Relative

mass

Symbol

or

or

Stopped by

In the following reactions, identify the type of decay as alpha, beta or gamma.

1. 146C 14

7N + 0-1e _______________________________

2. 22886 Rn 42He + 224

84Po _______________________________

3. 4018Ar 00 y + 40

18 Ar _______________________________

Balancing Nuclear Decay Equations:

Predict the product or reactant of the following nuclear reactions.

4. 22688 Ra 42He + _______________

5. ______________ 0+1e + 5325Mn

6. 11 H + 31 H _______________

Fission and Fusion:

Nuclear Fusion:

o Two smaller nuclei are coming together to form one larger, more stable nucleus.

o Examples of Sun and Hydrogen bomb.

Nuclear Fission:

o One large nuclei splits into two smaller and more stable nuclei.


o Examples of nuclear power plant and atomic bomb.

7. What is it called when a nucleus splits apart and releases massive amounts of energy?

____________________________________________

8. Which releases more energy fission or fusion?

____________________________________________

MOLE CONVERSIONS:

To calculate Molar Mass

EXAMPLE: NaCl

Molar mass of NaCl = (1 X 23.0 g/mole) + (1 X 35.5 g/mole) = 58.5 g/mole

Practice: Determine the molar mass for the following compounds:

9. Al(CH3CO2)3

10. C6H8O6

Mass of Na from

periodic table

Amount of

Na atoms in

the formula


Percent Composition:

How to Calculate % Composition Steps:

1. Calculate the molar mass of the compound. 2. Divide the total mass of the element by the molar mass of the compound. 3. Multiply step 2 by 100%.

Example: Find the percent of oxygen in KMnO4

Step 1:K: (1 X 39.1 g/mol) = 39.1 g/mol

Mn: (1 X 54.9 g/mol) = 54.9 g/mol

O: (4 X 16.0 g/mol) = 64.0 g/mol

Molar Mass = 39.1 g/mol + 54.9 g/mol + 64.0 g/mol = 158.0 g/mol

Step 2: 64.0 g/mol ÷ 158.0 g/mol = 0.41

Step 3: 0.41 X 100% = 41%

Practice: Determine the percentage composition of each in the compounds below.

11. Al(CH3CO2)3

Al= ___________________ C = ___________________ H = ___________________ O = ___________________

12. C6H8O6

C = ___________________ H = ___________________ O = ___________________

Mass of Na from

periodic table

Amount of

Na atoms in

the formula


Mole Conversions:

To calculate from grams to moles

𝑔𝑖𝑣𝑒𝑛 𝑔

1∗

1 𝑚𝑜𝑙

𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑔 = ____𝑚𝑜𝑙𝑒𝑠

To calculate from moles to grams

𝑔𝑖𝑣𝑒𝑛 (𝑚𝑜𝑙𝑒𝑠)

1∗𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑔

1 𝑚𝑜𝑙𝑒= ____𝑔𝑟𝑎𝑚𝑠

Example:

How many moles are in 125 grams of MgCl2?

125 𝑔𝑟𝑎𝑚𝑠

1∗

1 𝑚𝑜𝑙𝑒

95.3 𝑔𝑟𝑎𝑚𝑠= 1.3 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑀𝑔𝐶𝑙2

Practice:

Solve the following. Round your answers to the correct number of significant figures.

13. How many moles are in 125 grams of MgCl2?

14. How many grams are in 1.91 moles of Zn?

Conversion(s) needed:

1 mol = molar mass

Molar Mass = 1 mol


1 mol of MgCl2= 95.3 g/mol


To calculate from particles (atoms, formula units, molecules) to moles

𝑔𝑖𝑣𝑒𝑛 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠

1∗

1 𝑚𝑜𝑙

6.02 𝑋 1023𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠= ____𝑚𝑜𝑙𝑒𝑠

To calculate from moles to particles (atoms, formula units, molecules)

𝑔𝑖𝑣𝑒𝑛 (𝑚𝑜𝑙𝑒𝑠)

1∗

6.02 𝑋 1023𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠

1 𝑚𝑜𝑙𝑒= ___𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠

Example:

How many moles are in 1.5 x 1024molecules of CO2?

1.5 𝑥 1024 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠

1∗

1 𝑚𝑜𝑙

6.02 𝑋 1023𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠= 2.5 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐶𝑂2

Practice:


15. How many moles are in 1.5 x 1024molecules of CO2?

16. How many formula units are in 3.43 moles of LiF?


1 mol = 6.02 X 1023 particles (molecules, atoms)

6.02 X 1023 particles (molecules, atoms) = 1 mol


6.02 X 1023 particles (molecules, atoms) = 1 mol**On the formula Chart**


17. How many atoms are in 1 mole of potassium?

To calculate from particles (atoms, formula units, molecules) to grams

𝑔𝑖𝑣𝑒𝑛 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠

1∗

1 𝑚𝑜𝑙

6.02 𝑋 1023𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠∗𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑔

1 𝑚𝑜𝑙= _____𝑔𝑟𝑎𝑚𝑠

To calculate from grams to particles (atoms, formula units, molecules)

𝑔𝑖𝑣𝑒𝑛 (𝑔)

1∗

1 𝑚𝑜𝑙

𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑔 ∗

6.02 𝑋 1023𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠

1 𝑚𝑜𝑙 = _______𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠

Example:

Convert 6.52 X 1025 atoms of gold to grams.

6.52 𝑥 1025 𝑎𝑡𝑜𝑚𝑠

1∗

1 𝑚𝑜𝑙

6.02 𝑋 1023𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠∗

196.967 𝑔

1 𝑚𝑜𝑙= 21332

Practice:


18. Convert 6.52 X 1025 atoms of gold to grams.


1 mol = 6.02 X 1023 particles 1 mole = molar mass


1 mol = 6.02 X 1023 particles

1 mole = 196.967 g/mol


19. Convert 24.5 grams of K3PO4 to formula units.

20. Convert 51 grams of O2 to molecules.

Empirical Formulas (lowest whole number ratio):

How to calculate empirical formulas steps:

*Assume 100 gram sample if given percentages simply replace % for grams

*If not, use grams.

1. Convert grams to moles. 2. Divide by the smallest number of moles. 3. If the numbers aren’t whole numbers, the multiply by a common number. For example, if the answer is

1.25 multiply by 4. 4. The whole numbers become the subscripts in the formula. Write the formula in the order the elements

were given in the problem.

Practice:

21. What is the empirical formula of the compounds below?

a) 68.4% chromium, 31.6% oxygen

b) 74.0% carbon, 8.7% hydrogen and the rest nitrogen


Molecular Formulas (true formulas):

How to calculate molecular formulas steps:

1. Calculate the molar mass of the empirical formula. If the empirical formula is not provided, solve for it first.

2. Divide the molar mass of the molecular formula (given in the problem) by the molar mass of the empirical formula. This must be a whole number.

3. Multiply the answer from step 2 by each subscript in the empirical formula.

Practice:

Determine the molecular formulas of the compounds below.

22. A compound is 43.7% Phosphorus and 56.3% Oxygen. The molar mass of the compound is 284 g/mole. Calculate the molecular formula of the compound.

23. A compound with an empirical formula of CFBrO has a molar mass of 254.7 grams per mole. Calculate the molecular formula of the compound.

STOICHIOMETRY:

**Remember to ALWAYS start with a balanced chemical equation!!!**

Mole-Mole Conversions:

To calculate from moles to moles


Xmol given = X mole find (X

is from the balanced eq.)


𝑔𝑖𝑣𝑒𝑛 (𝑚𝑜𝑙)

1∗

𝑥 𝑚𝑜𝑙 𝑜𝑓𝑓𝑖𝑛𝑑

𝑤𝑎𝑛𝑡

𝑥 𝑚𝑜𝑙 𝑜𝑓 𝑔𝑖𝑣𝑒𝑛= _____𝑚𝑜𝑙𝑒𝑠

Example:

How many moles of sodium oxide are produced when 3.90 moles of sodium combine with oxygen gas?

__Na + __O2___Na2O

3.90 𝑚𝑜𝑙𝑒𝑠 𝑁𝑎

1∗

2 𝑚𝑜𝑙𝑒𝑠 𝑁𝑎2𝑂

4 𝑚𝑜𝑙𝑒𝑠 𝑁𝑎= 1.95 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑁𝑎2𝑂

Practice:

Solve the following round your answer to the correct number of significant figures.

24. Given: ____NH3 + ____NO ____N2 + ____H2O a. How many moles of NO are needed to react with 15.0 moles of NH3?

b. How many moles of water are produced if 2.45 moles of NO react with NH3?

Mole-Mass Conversions:

To calculate from moles to mass

𝑔𝑖𝑣𝑒𝑛 (𝑚𝑜𝑙)

1∗


𝑤𝑎𝑛𝑡

𝑥 𝑚𝑜𝑙 𝑜𝑓 𝑔𝑖𝑣𝑒𝑛∗𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑜𝑓

𝑓𝑖𝑛𝑑

𝑤𝑎𝑛𝑡

1 𝑚𝑜𝑙 𝑜𝑓𝑓𝑖𝑛𝑑

𝑤𝑎𝑛𝑡

= ___𝑔𝑟𝑎𝑚𝑠

Example:

Balance

first!!

4Na + 1O2 2Na2O

Balance first!!


Xmol given = X mole find (X is from the balanced eq.)

1 mole = molar mass


How many grams of sodium oxide are produced when 3.90 moles of sodium combine with oxygen gas? __Na + __O2___Na2O 4Na + 1O2 2Na2O

3.90 𝑚𝑜𝑙𝑒𝑠 𝑁𝑎

1∗


4 𝑚𝑜𝑙𝑒𝑠 𝑁𝑎∗

62. 𝑂 𝑔 𝑁𝑎2𝑂

1 𝑚𝑜𝑙𝑒 𝑁𝑎2𝑂= 121 𝑔𝑟𝑎𝑚𝑠 𝑁𝑎2𝑂

Practice:


25. Given: ____Hg + ____Br2 ____HgBr2

How many grams of mercury (II) bromide are produced when 3.21 moles of mercury react with bromine gas?

Mass-Mole Conversions:



1∗

1 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑔𝑖𝑣𝑒𝑛

𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑔𝑖𝑣𝑒𝑛∗


𝑤𝑎𝑛𝑡

𝑥 𝑚𝑜𝑙 𝑜𝑓 𝑔𝑖𝑣𝑒𝑛= _____𝑚𝑜𝑙𝑒𝑠

Example:

How many moles of sodium oxide are produced when 3.90 grams of sodium combine with oxygen gas?

__Na + __O2___Na2O 4Na + 1O22Na2O

Balance first!! Conversion(s) needed:

4mol Na = 2 mole Na2O

1 mole Na2O= 62.0 grams Na2O



1 mole = molar mass

Balance first!!


4mol Na = 2 mole Na2O

1 mole Na = 23.0 grams Na


3.90 𝑔 𝑁𝑎

1∗

1 𝑚𝑜𝑙𝑒𝑠 𝑁𝑎

23.0 𝑔𝑟𝑎𝑚𝑠 𝑁𝑎∗


4 𝑚𝑜𝑙𝑒 𝑁𝑎

Practice:


26. Given: ____Hg + ____Br2 ____HgBr2

How many moles of bromine gas are required to produce 10.0 g of mercury (II) bromide?

Mass-Mass Conversions:



1∗

1 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑔𝑖𝑣𝑒𝑛

𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑔𝑖𝑣𝑒𝑛∗

𝑥 𝑚𝑜𝑙𝑒 𝑜𝑓𝑓𝑖𝑛𝑑

𝑤𝑎𝑛𝑡

𝑥 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑔𝑖𝑣𝑒𝑛∗𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑜𝑓

𝑓𝑖𝑛𝑑

𝑤𝑎𝑛𝑡

1 𝑚𝑜𝑙𝑒 𝑜𝑓𝑓𝑖𝑛𝑑

𝑤𝑎𝑛𝑡

= ____𝑔𝑟𝑎𝑚𝑠

Example:

How many grams of sodium oxide are produced when 3.90 grams of sodium combine with oxygen gas?

__Na + __O2___Na2O 4Na + 1O2 2Na2O



1 mole = molar mass (given and want/find)

Balance first!!


2 mole Na2O = 4 moles Na

1 mole Na = 23.0 grams Na

1 mole Na2O = 62.0 grams Na2O


3.90 𝑔 𝑁𝑎

1∗

1 𝑚𝑜𝑙𝑒 𝑁𝑎

23.0 𝑔 𝑁𝑎∗


4 𝑚𝑜𝑙𝑒𝑠 𝑁𝑎∗

62.0 𝑔 𝑁𝑎2𝑂

1 𝑚𝑜𝑙𝑒 𝑁𝑎2𝑂= 5.26 𝑔𝑟𝑎𝑚𝑠 𝑁𝑎2𝑂

Practice:


27. If 59.3 grams of Iron (III) oxide react with carbon monoxide to produce iron and carbon dioxide, how many grams of carbon dioxide will be produced?

28. If 59.3 grams of Iron (III) oxide react with carbon monoxide to produce iron and carbon dioxide, how many grams of iron will be produced?

Limiting Reactant How to solve for a limiting reactant problem?

1. Determine if the problem is a limiting reactant problem, the problem will say“limiting” or you are given the mass for both reactants.

2. If an equation is written out for you balance the equation, otherwise write and balance the equation.

3. Set up a mass-mass problem for all of the givens remember to always solve for the same product. So if you have 2 reactants, you’re doing the problem twice.

4. The limiting reactant is always the reactant that gave you the least amount of product and the excess is the one that gave you the most.

Practice:

Given: Zn + 2HCl ZnCl2 + H2

If 56.7 g of zinc reacts with 70.0 grams of hydrochloric acid, determine the limiting reactant. Determine the maximum amount of zinc chloride that can be made?

1. Determine if the problem is a limiting reactant problem, the problem will say“limiting” or you are given the mass for both reactants.

Mass is given for both reactants = limiting reactant problem

56.7 grams of zinc & 70.0 grams of hydrochloric acid


2. If an equation is written out for you balance the equation, otherwise write and balance the equation.

Zn + 2HCl ZnCl2 + H2reaction is balanced

3. Set up a mass-mass problem for all of the givens remember to always solve for the same product. So if you have 2 reactants, you’re doing the problem twice.

56.7 𝑔 𝑍𝑛

1∗

1 𝑚𝑜𝑙𝑒 𝑍𝑛

65.38 𝑔 𝑍𝑛∗

1 𝑚𝑜𝑙𝑒𝑠 𝑍𝑛𝐶𝑙2

1 𝑚𝑜𝑙𝑒𝑠 𝑍𝑛∗

136.38 𝑔 𝑍𝑛𝐶𝑙2

1 𝑚𝑜𝑙𝑒 𝑍𝑛𝐶𝑙2

= 118.27𝑔𝑟𝑎𝑚𝑠 𝑍𝑛𝐶𝑙2

70.0 𝑔 𝐻𝐶𝑙

1∗

1 𝑚𝑜𝑙𝑒 𝐻𝐶𝑙

36.5 𝑔 𝐻𝐶𝑙∗


2 𝑚𝑜𝑙𝑒𝑠 𝐻𝐶𝑙∗

136.38 𝑔 𝑍𝑛𝐶𝑙2


= 130.78 𝑔𝑟𝑎𝑚𝑠 𝑍𝑛𝐶𝑙2

4. The limiting reactant is always the reactant that gave you the least amount of product.

56.7 𝑔 𝑍𝑛

1∗

1 𝑚𝑜𝑙𝑒 𝑍𝑛

65.38 𝑔 𝑍𝑛∗


1 𝑚𝑜𝑙𝑒𝑠 𝑍𝑛∗

136.38 𝑔 𝑍𝑛𝐶𝑙2


= 118.27𝑔𝑟𝑎𝑚𝑠 𝑍𝑛𝐶𝑙2

5. The excess reactant is always the reactant that gave you the most amount of product.


1 mole Zn = 1 moles ZnCl2 1 mole ZnCl2 = 2 moles 1mole ZnCl2 = 136.38 g ZnCl2

1 mole Zn = 65.39 grams Zn 1 mole HCl = 36.5 grams HCl

Limiting reactant since it produces the

smallest number of grams

Zn is the limiting reactant

118.27 grams is the maximum amount of

ZnCl2 that can be produced

Excess reactant since it produces the

largest number of grams


70.0 𝑔 𝐻𝐶𝑙

1∗

1 𝑚𝑜𝑙𝑒 𝐻𝐶𝑙

36.5 𝑔 𝐻𝐶𝑙∗


2 𝑚𝑜𝑙𝑒𝑠 𝐻𝐶𝑙∗

136.38 𝑔 𝑍𝑛𝐶𝑙2


= 130.78 𝑔𝑟𝑎𝑚𝑠 𝑍𝑛𝐶𝑙2

Practice:

29. Given: Zn + 2HCl ZnCl2 + H2

a) If 56.7 g of zinc reacts with 70.0 grams of hydrochloric acid, determine the limiting reactant.

b) What mass of zinc chloride will be produced by the reaction?

c) What mass of excess reagent remains after the reaction?

30. If 52.5 g of iron reacts with 30.0 grams of oxygen, what mass of iron (III) oxide will form?


Percent yield

How to solve for percent yield?

Step 1: If an equation is written out for you balance the equation, otherwise write and balance the equation.

Step 2: Set up a mass to mass stoichiometry problem to solve for the product stated in the problem. This is the theoretical yield.

Step 3: Determine the actual yield from the problem, this is the amount produced in the experiment or in a laboratory setting. Usually given in the problem.

Step 4: Plug in your information in the following equation: % yield = (actual yield/theoretical yield)*100%

Practice:

31. What is the percent yield of aluminum phosphate if a solution containing 33.4 g of sodium phosphate produced 19.6 g of aluminum phosphate when reacted with excess aluminum chloride

in solution?

___Na3PO4 + ___AlCl3 ___NaCl + ___AlPO4

32. If 84.8 grams of iron (III) oxide produces 57.8 grams of iron, what is the percent yield of

iron in the reaction? ___Fe2O3 + ___CO ___Fe + ___CO2


Answers:

1. beta 2. alpha 3. gamma 4. 222

86Rn 5. 53

26 Fe 6. 4

2 He 7. nuclear fission 8. nuclear fussion 9. 204.0 g/mol 10. 176.0 g/mol 11. Al = 13.2%, C = 35.3%,

H = 4.41%, O = 47.1% 12. C = 40.9%, H = 4.55%,

O = 54.5% 13. 1.31 mol 14. 125 g 15. 2.5 mol 16. 2.06 x 1024 formula

units

17. 6 x 1023 atoms 18. 21,300 atoms 19. 6.95 x 1022 formula

units 20. 9.6 x 1023 molecules 21. a) Cr2O3 b) C5H7N 22. P4O10 23. C2F2Br2O2 24. a) 22.5 mol NO b) 2.45

mol H2O 25. 1,160 g HgBr2 26. 0.0277 mol Br2 27. 49.0 g CO2 28. 41.5 g Fe

29. a) Zinc b) 118 g ZnCl2 c) 6.8 g of HCl in excess

30. 75.1 g of Fe2O3 31. 79.0% 32. 97.5%

Name: Date: Period: CBA REVIEW (Nuclear Chem. Mole Conversions, & Stoichiometry ... · ·...

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