Stoichiometry Problems
1. How many grams of Cu2S could be produced from 9.90 grams of CuCl
reacting with an excess of H2S gas?

2 CuCl(aq) + H2S(g)
Cu2S(s) + 2 HCl(aq)
2. In the decomposition of potassium chlorate, 82.6 g of O2 are formed.
How many grams of potassium chloride are produced?
2 KClO3(s)

2 KCl(s) + 3 O2(g)
3. Given the balanced equation:
4 NH3(g) + 5 O2(g)

4 NO(g) + 6 H2O(g)
How many grams of NH3 will be required to react with 80 g of O2 ?
4. How many grams of CO2 are formed when 32 g of O2 reacts with 23 g of
C2H5OH?
C2H5OH(l) + 3 O2(g)
 2 CO2(g) + 3 H2O(g)
5. Calculate the number of moles of each reactant required to make 7.24
moles of ammonia.
N2(g) + 3 H2(g)

2 NH3(g)
6. How many moles of ammonia can be produced from 8.0 moles of
hydrogen reacting with nitrogen?
3 H2(g) + N2(g)
 2 NH3(g)
7. What mass of hydrogen can be produced by reacting 6 moles of
aluminum with hydrochloric acid?
2 Al(s) + 6 HCl(aq)
 2 AlCl3(aq) + 3 H2(g)
8. How many moles of water can be produced by burning 325 grams of
octane (C8H18)?
2 C8H18(g) + 25 O2(g)
 16 CO2(g) + 18 H2O(g)
9. How many grams of silver nitrate are required to produce 0.25 mol of
silver sulfide?
2 AgNO3(aq) + H2S(g)
 Ag2S(s) + 2 HNO3(aq)
10. Sodium chloride is prepared by the reaction of sodium metal with
chlorine gas.
2 Na(s) + Cl2(g)
 2 NaCl(s)
What will occur when 6.70 moles of Na reacts with 3.80 moles of Cl2?
a) What is the limiting reagent?
b) How many moles of NaCl are produced?
c) How much of the excess reagent remains unreacted?
11. Copper reacts with sulfur to form copper(I) sulfide.
2 Cu(s) + S(s)
 Cu2S(s)
What is the maximum number of grams of Cu2S that can be formed when
80 g of Cu reacts with 25 g of S?
12. Carbon tetrachloride was prepared by reacting 100 g of carbon
disulfide and 100 g of chlorine. Calculate the percent yield if 65 g of
CCl4 was obtained from the reaction.
CS2 + 3 Cl2
 CCl4 + S2Cl2