Question

Why will the colour of heated copper powder become black when air is passed over it

Answer 1

as it gets oxidised and form cupric oxide which is black in colour

Answer 2

》Because, when it is heated then there is a reaction with the oxygen and this reaction became a black. The color of the heated copper powder becomes black when air is passed over it because of its reaction with oxygen i.e.air. When it reacts with oxygen it formscopper oxide which is black incolor.