Question

When 2.0 g copper is heated with an excess of sulfur, copper (I) sulfide is the product. What is the mass of the copper (I) sulfide produced? (mass to mass)

Answer 1

Answer: Mass is 2.50 g

Explanation: reaction 2 Cu + S ⇒ Cu2S

Amount of Cu = m/M = 2.00 g /63.55 g/mol= 0.03147 mol

Amount of Cu2S = 0.5 n(Cu) = 0.01574 mol

M(Cu2S)= 159.17 g/mol, m = n·M