You have 47.2 mL of a solution of copper(II) chloride (CuCl2?). You need to determine the concentration of Cu2+ in the solution gravimetrically. You add an excess of aqueous sodium sulfide and isolate 96.0 mg of CuS. What was the concentration of the original CuCl2 solution?
CuCl2 + S2- → CuS(s) + 2Cl?-