Stoichiometry Practice Test Answers
Mass-Mass, Mass-Mole, Mole-Mass Problems (Determine which one by READING the question):
1. Copper metal reacts with silver nitrate (copper(II) nitrate is one product). How many grams of copper
are required to form 250 g of silver? Equation: Cu + 2 AgNO3 2 Ag + Cu(NO3)2 Answer 74 g
2. When aluminum is burned in excess oxygen, aluminum oxide is produced. How many grams of oxygen
are required to produce 0.75 moles of Al2O3? Equation: 4 Al + 3 O2 2 Al2O3 Answer : 36 g
3. When 9.34 g of zinc react with excess hydrochloric acid how many grams of zinc chloride will be
produced? Equation: Zn + 2 HCl ZnCl2 + H2 Answer: 19.5 g
4. If 25.3 g of aluminum reacts with 25.3 g of copper(II) sulfate, how many grams of copper are formed? Identify the limiting and excess reactants in this single replacement reaction.
Equation: 2 Al + 3 CuSO4 3 Cu + Al2(SO4)3 Answer: 10.0 g LR: copper sulfate XR: Al
5. If 12.5 g of copper react with excess chlorine gas, then 25.4 g of copper(II) chloride are produced. Find
the theoretical and percent yields. Equation: Cu + Cl2 CuCl2 Answer: Theoretical: 26.4 g % yield: 96.2% Stoichiometry Practice Test
Mass-Mass, Mass-Mole, Mole-Mass Problems (Determine which one by READING the question):
1. How many grams of iron(III) chloride are produced when 15.3 g of iron react with excess chlorine gas?
Equation: 2 Fe + 3 Cl2 2 FeCl3 Answer: 44.4 g
2. Copper metal reacts with silver nitrate to form silver and copper (II) nitrate. How many grams of silver
will be produced from 3.65 moles of silver nitrate? Equation: Cu + 2 AgNO3 2 Ag + Cu(NO3)2 Answer: 394 g
3. Zinc reacts with hydrochloric acid to produce zinc chloride and hydrogen. How many grams of HCl are
required to produce 7.50 moles of ZnCl2? Equation: Zn + 2 HCl ZnCl2 + H2 Answer: 547 g
4. When 16.3 g of magnesium and 4.52 g of oxygen gas react, how many grams of magnesium oxide will be formed? Identify the limiting and excess reactants.
Equation: 2 Mg + O2 2 MgO
Answer: LR: O2 XS: Mg Product: 11.4 g MgO
5. If 6.57 g of iron react with an excess of hydrochloric acid, HCl, then 11.2 g of iron(II) chloride are obtained in addition to hydrogen gas. Find the theoretical and percent yields of iron (II) chloride.
Equation: Fe + 2 HCl FeCl2 + H2
Answer: Theoretical: 14.9 g FeCl2 Percent Yield: 75.1% Stoichiometry Practice Test
Mass-Mass, Mass-Mole, Mole-Mass Problems (Determine which one by READING the question):
1. Copper metal reacts with silver nitrate (copper(II) nitrate is one product). How many grams of copper
are required to form 250 g of silver? Equation: Cu + 2 AgNO3 2 Ag + Cu(NO3)2 Answer 74 g
2. When aluminum is burned in excess oxygen, aluminum oxide is produced. How many grams of oxygen
are required to produce 0.75 moles of Al2O3? Equation: 4 Al + 3 O2 2 Al2O3 Answer : 36 g
3. When 9.34 g of zinc react with excess hydrochloric acid how many grams of zinc chloride will be
produced? Equation: Zn + 2 HCl ZnCl2 + H2 Answer: 19.5 g
4. When 16.3 g of magnesium and 4.52 g of oxygen gas react, how many grams of magnesium oxide will be formed? Identify the limiting and excess reactants.
Equation: 2 Mg + O2 2 MgO
Answer: LR: O2 XS: Mg Product: 11.4 g MgO
5. If 6.57 g of iron react with an excess of hydrochloric acid, HCl, then 11.2 g of iron(II) chloride are obtained in addition to hydrogen gas. Find the theoretical and percent yields of iron (II) chloride.
Equation: Fe + 2 HCl FeCl2 + H2
Answer: Theoretical: 14.9 g FeCl2 Percent Yield: 75.1%