1 g of copper powder was taken in a China dish and heated. What change takes place on heating?
When hydrogen gas is passed over this heated substance, a visible change is seen in it. Give the chemical equations of reactions, the name, and the color of the products formed in each case.
When the copper powder is heated in a china dish, the copper powder surface becomes coated with a black colour substance due to the formation of ‘copper oxide’ by surface oxidation.
$2Cu(s) + O_2 (g) → 2CuO(s)$
When hydrogen gas is passed over the hot copper oxide, it is reduced to its basic metal form.
$CuO(s) + H_2(g)→ Cu(s) + H_2O(l) $
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