Be sure to answer all parts. The concentration of Cu²⁺ ions in the water (which also contains sulfate ions) discharged from a certain industrial plant is determined by adding excess sodium sulfide (Na₂S) solution to 0.400 L of the water. The molecular equation is Na₂S(aq) + CuSO₄(aq)

Na₂SO₄(aq) + CuS(s) Calculate the molar concentration of Cu²⁺ in the water sample if 0.0303 g of solid CuS is formed.