Determine the mass of phosphorus oxide (5), which is formed during the combustion of 9.3 g of white phosphorus.

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 due to the fact that the oxide molecule contains two phosphorus atoms.

Let’s calculate the chemical amount of a substance that is in 9.3 grams of white phosphorus.

M P = 31 grams / mol;

N P = 9.3 / 31 = 0.3 mol;

Let us calculate the weight 0.3 / 2 = 0.15 mol of pentavalent oxide.

M P2O5 = 31 x 2 + 5 x 16 = 142 grams / mol;

The weight of the oxide will be:

m P2O5 = 142 x 0.15 = 21.3 grams;