Determine the mass of phosphorus required to react with 15 g of oxygen to obtain phosphorus (V) oxide.

The phosphorus combustion reaction is described by the following chemical reaction equation:

2P + 5/2 O2 = P2O5;

When 2 moles of phosphorus are burned, 1 mole of its pentavalent oxide is formed. This is because the oxide molecule contains two phosphorus atoms. This requires 2.5 moles of oxygen.

Let’s calculate the chemical amount of a substance that is in 320 grams of oxygen.

M O2 = 32 grams / mol;

N O2 = 15/32 = 0.46875 mol;

We calculate the weight of 0.46875 x 5/2/2 = 0.5859 mol of phosphorus.

M P = 31 grams / mol;

The weight of phosphorus will be:

m P = 31 x 0.5859 = 18.16 grams;