Question

If copper metal is heated over a flame it develops a coating.what is the colour and composition of this coating?

Answer 1

when copper is heated oxygen combines with oxygen to form copper oxide.
colour of copper changes to black.
2cu+o2__________=2cu
reaction is above

Answer 2

When copper is heated over the flame it reacts with oxygen present in the air and forms a black coating called copper oxide

I hope this answer will help you