Soundarya took $1 g$a copper powder from a china dish and heated it. She then passed hydrogen gas over this heated substance and observed a visible change. What are the changes observed by her in each case? Explain with the help of a chemical equation.

When $1 g$ of copper powder is taken in a china dish and heated, a black-colored substance is formed, called copper oxide.

The copper gets oxidized to copper oxide. $CuO$ and copper metal is obtained when hydrogen gas is passed over this heated substance.
The black-colored $CuO$ is reduced, and brown color $Cu$ metal is produced.