When copper(II) oxide is heated in the presence of hydrogen gas, elemental copper and water are produced. What mass of copper can be obtained if 22.8 g copper(II) oxide is used?

Answer 1

Here is a solved example of a stoichiometry problem. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html
Post your work if you get stuck.

Answer 2

Fgc