1. When copper is heated with an excess of sulfur, copper(I) sulfide is formed. In a given experiment, 0.0970 moles of copper was heated with excess sulfur to yield 5.84 g copper(I) sulfide. What is the percent yield?

2. One of the commercial uses of sulfuric acid is the production of calcium sulfate and phosphoric acid. If 24.2 g of Ca(PO) reacts with 54.3 g of HSO, what is the percent yield if 10.9 g of HPO is formed via the UNBALANCED equation below? Ca(PO) (s) + HSO (aq) HPO (aq) + CaSO (aq)

3. If 23.9 g of NO and 13.8 g of O are used to form NO, how many moles of excess reactant will be left over? 2 NO (g) + O (g) 2 NO (g)