ANSWERS: Limiting Reagents (Limiting Reactants)!!
For the following reactions, find the following:
a)
Which of the reagents is the limiting reagent?
b)
What is the maximum amount of each product that can be formed?
c)
How much of the other reagent is left over after the reaction is complete?
1)
Consider the following reaction:
3 NH4NO3 + Na3PO4  (NH4)3PO4 + 3 NaNO3
Answer the questions above, assuming we started with 30 grams of ammonium
nitrate and 50 grams of sodium phosphate.
a) NH4NO3 is the limiting reactant
b) 31.859 g NaNO3 and 18.626 g (NH4)3PO4
c) 29. 52 g excess Na3PO4
2)
Consider the following reaction:
3 CaCO3 + 2 FePO4  Ca3(PO4)2 + Fe2(CO3)3
Answer the questions at the top of this sheet, assuming we start with 100 grams
of calcium carbonate and 45 grams of iron (III) phosphate.
a) FePO4 is the limiting reactants
b) 46.27 g Ca3(PO4)2 and 43.52 g Fe2(CO3)3
c) 55.203 g excess CaCO3
ANSWERS: Percent Yield Problems
1. A student adds 200.0g of C7H6O3 to an excess of C4H6O3, this produces C9H8O4 and C2H4O2.
Calculate the percent yield if 231 g of aspirin (C9H8O4) is produced.
C7H6O3 + C4H6O3  C9H8O4 + C2H4O2
Percent Yield = 88.55%
2. According to the following equation, Calculate the percentage yield if 550.0 g of toluene
()added to an excess of nitric acid () provides 305 g of the p-nitrotoluene product.
C7H8 + HNO3  C7H7NO2 = H2O
Percent Yield = 37.26%
3. Quicklime, CaO, can be prepared by roasting limestone, CaCO3, according to the chemical
equation below. When 2.00 x 103 g of CaCO3 are heated, the actual yield of CaO is 1.10 x 103 g.
What is the percentage yield?
CaCO3  CaO + CO2
Percent Yield = 98.16%
4. Aluminum reacts with an aqueous solution containing excess copper (II) sulfate. If 1.85 g Al
reacts and the percentage yield of Cu is 56.6%, what mass of Cu is produced?
Al + CuSO4 
Cu + Al2(SO4)3
Actual Yield = 3.70 g Cu
5. The combustion of methane produces carbon dioxide and water. Assume that 2.0 mol of CH4
burned in the presence of excess air. What is the percentage yield if the reaction produces 87.0 g
of CO2?
Percent Yield = 98.84%