What happens when (a) ZnCO3 is heated in the absence of oxygen? (b) a mixture of Cu2O and Cu2S is heated?

Soln:

1. When ZnCO3 is heated in the absence of oxygen Zinc Oxide and Carbon-di-oxide are

ZnCo₃ ZNO + CO₂

1. When a mixture of Cu2O and Cu2S is heated we get pure copper 2 Cu2O+ Cu2S6Cu+SO₂