What amount of oxygen substance entered into the reaction of phosphorus combustion

What amount of oxygen substance entered into the reaction of phosphorus combustion if 4 mol 5 (P2O5) was formed as a result of the reactions?

The combustion reaction of phosphorus is described by the following chemical reaction equation.

2P + 5/2 O2 = P2O5;

The phosphorus oxide molecule consists of 2 phosphorus atoms and 5 oxygen atoms. When 2 moles of phosphorus are burned, 1 mole of its oxide is formed. This requires 2.5 moles of oxygen. Since in the oxide molecule there are 5 oxygen atoms, and in the oxygen molecule there are 2 oxygen atoms.

Therefore, for the formation of 4 moles of phosphorus oxide, 4 x 5/2 = 10 moles of oxygen will be required.