Percent Yield
Practice Problems
Chemistry 20
1. The actual amount of product in a reaction is 39.7 g although a mass-mass
calculation predicted 65.6g. What is the percent yield?
2. What is the %yield in the following reaction if 5.50g of hydrogen reacts with an
excess amount of nitrogen to form 20.4 g of ammonia?
3 H2 + N2  2 NH3
3. In a reaction to produce xenon tetrafluoride, 1.58 g of xenon reacts with excess
fluorine. IF the actual yield was 0.11 g for XeF4 what was the percent yield?
Xe + 2F2  XeF4
4. Pure iron can be produced by the reaction between magnetite (Fe3O4) and
hydrogen gas. Water is also a product. If 100.0g of both magnetite and hydrogen
are initially present, what is the limiting reagent and calculate the percent yield if
32.0g of Fe was actually isolated.
5. One of the reactions involved in smelting copper sulfide ores involves copper(I)
oxide and copper(II) sulfide:
2 Cu2O + Cu2S  6Cu + SO2
If 50.0g of copper(I) oxide is heated with 25.8g of copper(II) sulfide:
a. Determine the limiting reagent
b. Calculate the theoretical yield of copper
c. Determine the %yield if 58.0g of copper is actually isolated.