How much oxygen is required to obtain 360 g of water?

Decision:
1. Let’s compose the reaction equation:
2H2 + O2 = 2H2O;
2. Let’s define М (Н2О) = (1 * 2) + 16 = 18 g / mol;
M (O2) = 16/2 = 32 g / mol.
3. Find the amount of substances (Y):
Y (O2) = m (O2) / M (O2);
Y (H2O) = m (H2O) / M (H2O);
Y (H2O) = 360/18 = 20 mol.
4.x mol O2 / 1 mol + 2H2 = 20 mol H2O / 2 mol, based on this proportion
Y (O2) = 20 * 1/2 = 10 mol.
5. Find m (O2) by the formula:
m (O2) = Y (O2) * M (O2);
m (O2) = 10 * 18 = 180 g;
Answer: m (O2) = 180 g.