Explain giving equation, what happens when:
(a) ZnCO3 is heated in the absence of air?
(b) a mixture of Cu2O and Cu2S is heated?
(a) When zinc carbonate is heated strongly in the absence of air, it decomposes to form zinc oxide and carbon dioxide.
(b) When copper (I) oxide reacts with copper (I) sulphide, it forms copper metal and sulphur dioxide.