A copper wire with a mass of 4.32 g reacts with sulfur to form 5.41 g of a copper sulfide compound. a) Determine the number of moles of copper and sulfur in the compound. b) Determine the empirical formula of the product. c) If the actual formula of the sulfide compound contains 1 S, what is the molecular formula of the compound? d) Write the balance equation for the combination reaction.