.What happens when
(a) ZnCOs is heated in the absence of oxygen?
(b) a mixture of Cu2O and Cu2S is heated?
Answers
(a) When Zinc Carbonate (ZnCO3) is heated in the absence of Oxygen, Zinc Oxide (ZnO) and Carbon Dioxide (CO2) are produced.
ZnCO3 → ZnO + CO2
(b) When a mixture of Copper Oxide (Cu2O) and Copper Sulphide (Cu2S) is heated, pure copper is obtained along with Sulphur Dioxide (SO2). It undergoes auto reduction.
2Cu2O + Cu2S → 6Cu + SO2
Explanation:
(a) The process of reduction carbonate ores to form oxides in absence of oxygen is called calcination. Zinc is found in its ore – zinc carbonate. When this ore is heated, Zinc Oxide (ZnO) is formed along with Carbon Dioxide (CO2).
(b) When sulphide ore of copper is heated, a part of this ore is converted into oxide which then reacts with remaining sulphide ore to give pure copper and Sulphur Dioxide (SO2).