1. STOICHIOMETRY REVIEW ANSWERS

2. 1. The calculation of quantities in chemical equations is called
Stoichiometry
2. The first step in most stoichiometry problems is to convert given quantities to
Moles
3. When two substances react to form products, the reactant which is used up is called the
Limiting Reagent

3. 4. The amount of product that forms when a reaction is carried out in the laboratory is the
Actual Yield
5. The maximum amount of products that could be formed from given amounts of reactants is the
Theoretical Yield
6. When an equation is used to calculate the amount of product that will form during a reaction, then the value obtained is called the

4. 2Al(s) + 3Pb(NO3)2(aq)  2Al(NO3)3(aq) + 3Pb(s)7.
2Al(s) + 3Pb(NO3)2(aq)  2Al(NO3)3(aq) + 3Pb(s)
A.) 2 moles Al + 3 molecules Pb(NO3)2  2 molecules Al(NO3)3 + 3 moles Pb F
B.) 2 grams Al + 3 grams Pb(NO3)2  2 grams Al(NO3)3 + 3 grams Pb
C.) 2 moles Al + 3 moles Pb(NO3)2  2 moles Al(NO3)3 + 3 moles Pb T
8. In every chemical reaction ___________ stay the same.
The Mass
9. In the reaction 2CO + O2  2CO2, what is the ratio of moles of oxygen used to moles of CO2 produced?
1:2

5. 10. For C5H12 + 8O2  5CO2 + 6H2O
______ moles of reactants chemically change into ______ moles of product.
9 moles of reactant to 11 moles of product

6. 11. How many moles of oxygen are required to react completely with 14
11. How many moles of oxygen are required to react completely with mol Al when given 4Al + 3O2  2Al2O3?
3 mol O2 =
14.8 mol Al x
11.1 mol O2
4 mol Al

7. 12. Given the balanced equation HCl + 2KMnO4  2KCl + 2MnCl2 + 5Cl2 + 8H2O if 2.0 mol of KMnO4 reacts, how many moles of H2O are produced?
8.0 mol H2O

8. Based on… 16HCl + 2KMnO4  2KCl + 2MnCl2 + 5Cl2 + 8H2O …how many grams of KCl are produced when 3.0 mol of KmnO4 reacts?
3.0 mol KMnO4 x
2 mol KCl
74.5 g KCl =
220 g KCl X
2 mol KMnO4
1 mol KCl

9. 14. If CuO + H2  Cu + H2O, how many moles of H2O are produced when 240 grams of CuO react?
240 g CuO x
1 mol CuO
1 mol H2O = X
3.0 mol H2O
80 g CuO
1 mol CuO

10. 15. In the reaction Zn + H2SO4  ZnSO4 + H2 how many grams of H2SO4 are required to produce 2.3 gram of H2?
1 mol H2
1 mol H2SO4
98 g H2SO4 =
2.3 g H2 x x x
1 mol H2SO4
2 g H2
1 mol H2
113 g H2SO4

11. 16. LiOH + HBr  LiBr + H2O. If you start with 15
16. LiOH + HBr  LiBr + H2O If you start with 15.0 grams of lithium hydroxide, how many grams of lithium bromide will be produced?
54.4 g LiBr

12. 17. How many molecules of oxygen are required to react completely with X 1023 molecules Al when given 4Al + 3O2  2Al2O3?
2.96 x 1023 molecules Al x
3 molecules O2 =
4 molecules Al
2.22 x 1023 molecules O2

13. 18. How many molecules of oxygen are produced by the decomposition of 6.54 g of potassium chlorate (KClO3)? KClO3  2KCl + 3O2
6.54 g KClO3 x
1 mol KClO3
3 mol O2
6.02 x 1023 molecules O2 = x x
122.5 g KClO3
2 mol KClO3
1 mol O2
4.82 x 1022 molecules O2

14. Convert 20 grams of LiOH  Grams of LiCl
LiOH + KCl  LiCl + KOH
A) I began this reaction with 20 grams of lithium hydroxide.
What is my theoretical yield of lithium chloride?
Convert 20 grams of LiOH  Grams of LiCl
35 g LiCl
B) I actually produced 6 grams of lithium chloride. What is my percent yield?
Actual
17%
X 100 =
_________
Theoretical

15. Convert 5 grams C3H8  Grams of H2O
20. C3H8 + 5 O2  3 CO2 + 4 H2O
A) If I start with 5 grams of C3H8, what is my theoretical yield of water?
Convert 5 grams C3H8  Grams of H2O
8.2 g H2O
B) I made 6.1 g of water. What was my percent yield?
Actual
74%
X 100 =
_________
Theoretical

16. ___ 42% Actual = Theoretical X 100
Be + 2 HCl  BeCl2 + H2 My theoretical yield of beryllium chloride was 10.7 grams. If my actual yield was 4.5 grams, what was my percent yield?
___
Actual
42% =
X 100
Theoretical

17. CaSO4 + NaI  CaI2 + Na2SO4 If 34. 7 g of calcium sulfate and 58
CaSO NaI  CaI Na2SO4 If 34.7 g of calcium sulfate and 58.3 g of sodium iodide are placed in a reaction vessel, what will be the limiting reagent?
NaI
Note: Refer to Limiting Reagent Notes to see how to work it out.