Determine the amount of hydrogen required to replace all copper from a 640 mg sample of copper (II) oxide.

Reaction: CuO + H2 = Cu + H2O
Let us find the amount of copper oxide substance n = m / M = 640,000 g / 79.5 g / mol = 8050 mol. M – molar mass, determined by the periodic table. By reaction with 1 mol of copper oxide, 1 mol of hydrogen reacts, which means n (CuO) = n (H2) = 8050 mol. Then the volume of hydrogen V = n * Vm = 8050 mol * 22.4 l / mol = 180 320 liters. Vm – molar volume, constant for all gases under normal conditions.
Answer: 180 320 liters of hydrogen will be required.