A student is doing the experiment Chemical Formulas of Copper Sulfide by heating copper with excess of sulfur at very high temperatures using a Bunsen burner. Copper and sulfur react stoichiometrically and excess of sulfur escapes from the crucible as sulfur dioxide. He collected the following data:
Mass of crucible, cover, and copper 20.015 g
Mass of crucible and cover 19.548 g
Mass of crucible, cover, and copper sulfide 20.135 g
Determine the empirical formula of copper sulfide. Show calculations.