Calculate the mass of phosphorus required to react with 11.2 L of oxygen

The reaction equation is:

4P + 5O2 = 2P2O5;

Mole oxygen:

n (O2) = V (O2): Vm = 11.2 L: 22.4 L = 0.5 mol;

Based on the coefficients, the amount of moles of phosphorus will be 1.25 times less than oxygen (5: 4 = 1.25). Therefore:

n (P) = 0.5: 1.25 = 0.4 mol;

The mass of phosphorus will be equal to:

m (P) = n (P) * M (P) = 0.4 mol * 31 g / mol = 12.4 g;