Limiting Reagent and Percent Yield Problems

  1. Given the following reaction, a student heated 5.25g of copper and 10.1g of sulfur.

∆

____Cu (s) + ____ S (s) ____Cu2S (s)

  1. What is the limiting reagent?
  1. How much of the product Cu2S is produced?
  1. How much of the excess reactant will be left over?

2.a. If 4.0 g of H2 are made to react with excess CO, how many grams of CH3OH can theoretically be produced according to the following equation?

CO(g) + 2H2(g) → CH3OH(l)

b. If 28.0 g of CH3OH are actually produced in 1(a), what is the percent

yield?

3.Given the following reaction: CaCO3(s) –→ CaO(s) + CO2(g)
If 50.8 grams of CaCO3 react to produce 26.4 grams of CaO, What is the percent yield of CaO?

4.____ Na (s) + ____ O2 (g) ____Na2O (s)

What is the maximum number of grams of Na2O that can be formed when 64.0 g of Na reacts with 28.5 g of O2?

5.A 5.00 × 102 g sample of Al2 (SO4)3 is made to react with 450.0 g of Ca(OH)2. A total of 554 g of CaSO4 is actually produced. The balanced equation is:
Al2(SO4)3(aq) + 3 Ca(OH)2(au) –→ 2 Al(OH)3 (s) + 3 CaSO4(s)

  1. What is the limiting reagent in this reaction?
  1. What is the theoretical amount of CaSO4 produced?
  1. What is the percent yield of CaSO4?

6.Ammonia and copper (II) oxide react according to the following equation:
2NH3(g) + 3CuO(s) –→ N2(g) + 3Cu(s) + 3H2O(g).

  1. If 57.0 g of ammonia are combined with 290.0 g of copper (II) oxide, identify the limiting reactant.
  1. What mass of nitrogen gas is produced, in grams?

7.Using the following unbalanced equation, what is the percent yield if a chemist begins with 66.0 g of Cr(OH)3 and produces of 38.4 g of NaCr(OH)4?

____NaOH (aq) +____Cr(OH)3 (s) ____NaCr(OH)4 (aq)