Stoich Test Review
Use the reaction below to answer the following questions:
3 Zn + 2 H3PO4  Zn3(PO4)2 + 3 H2
1. What mass of phosphoric acid is required to produce 15 g of hydrogen gas?
3 Zn + 2 H3PO4  Zn3(PO4)2 + 3 H2
2. What is the total number of moles of Zn needed to react completely with 5.2 moles of phosphoric
acid?
3 Zn + 2 H3PO4  Zn3(PO4)2 + 3 H2
3. How many moles of zinc phosphate will be formed when 2.52 g of zinc completely reacts with
phosphoric acid?
3 Zn + 2 H3PO4  Zn3(PO4)2 + 3 H2
4. Determine the total number of grams of zinc needed to produce 0.536 moles of hydrogen gas.
3 Zn + 2 H3PO4  Zn3(PO4)2 + 3 H2
5. Determine the number of grams of hydrogen gas produced if 2.15 g of phosphoric acid reacts
completely with zinc metal.
3 Zn + 2 H3PO4  Zn3(PO4)2 + 3 H2
6. In a certain experiment, 0.025 g of hydrogen gas is produced when 1.25 g of zinc reacts completely
with phosphoric acid. What was the percent yield for the reaction?
3 Zn + 2 H3PO4  Zn3(PO4)2 + 3 H2
7. In a certain experiment, 0.25 g of zinc phosphate is produced when 1.25 g of phosphoric acid reacts
completely with zinc. What was the percent yield for the reaction?
3 Zn + 2 H3PO4  Zn3(PO4)2 + 3 H2
Use the reaction below to answer the following questions:
4 Al + 3 O2  2 Al2O3
1. 2.5 g of Al reacts with 6.25 g of oxygen gas.
a. Determine the limiting reactant.
b. Determine how many grams of aluminum oxide will be produced (theoretical yield).
c. If 0.125 g of aluminum oxide is produced, calculate the percent yield.
2. 1.25 moles of aluminum reacts with 5.25 moles of oxygen gas.
4 Al + 3 O2  2 Al2O3
a. Determine the limiting reactant.
b. Determine the moles of aluminum oxide that will be produced.
c. Determine the number of grams of aluminum oxide that will be produced.
d. If 10.25 g of aluminum oxide is produced, calculate the percent yield.
3. Zinc metal is placed into a beaker of copper (I) chloride and allowed to react.
a. Write the reaction.
b. 0.656 g of Zinc reacted. Calculate the number of moles of zinc that reacted in the
experiment.
c. Based on your answer above, calculate the number of moles of copper that should be
produced in the reaction.
d. If 0.005 moles of copper are actually produced, calculate the percent yield of the reaction.