Question

You might have noted that when copper powder is heated in a china dish, the reddish brown surface of copper powder becomes coated with a black substance.
(a) Why has this black substance formed ?
(b) What is this black substance formed ?
(c) Write the chemical equation of the reaction that takes place.
(d) How can the black coating on the surface be turned reddish brown?

Answer 1

Answer:

This is because the copper powder present in the china dish reacts with the atmospheric oxygen and forms copper (II) oxide. The compound formed copper (II) oxide is generally black in colour and thus, the surface of copper powder is coated with this black copper (II) oxide because of the surface oxidation of copper.