what mass of hydrogen is needed to react with 40.0g of copper oxide how do I do this questions I have no idea
So hydrogen and copper oxide as educts react to the products copper and water?
Spoiler
Every copper atom has a mass of 63.5 g, every hydrogen 1 g and every oxygen 16 g. So Cu = 63.5 g, CuO = 79.5 g, H2 = 2 g and H2O = 18 g. You can solve it by the rule of three.<- use another colour to see masses were written in white!