How much oxygen is required to burn 20 g of phosphorus containing 10% impurities?

How much oxygen is required to burn 20 g of phosphorus containing 10% impurities? What mass of phosphorus oxide (4) is formed in this case?

The reaction of phosphorus with oxygen occurs in accordance with the following chemical reaction equation:

P + O2 = PO2;

For oxidation of 1 mol of phosphorus, 1 mol of oxygen is required.

Let’s find the amount of phosphorus.

M P = 31 grams / mol;

N P = 20 x 0.9 / 31 = 0.58 mol;

To burn this amount of phosphorus, 0.58 mol of oxygen is required. The same amount of phosphorus oxide will be obtained.

Let’s find its volume.

One mole of gas under normal conditions fills a volume of 22.4 liters.

The oxygen volume will be equal to:

V O2 = 0.58 x 22.4 = 12.992 liters;

The mass of phosphorus oxide will be:

M PO2 = 31 + 16 x 2 = 63 grams / mol;

m PO2 = 63 x 0.58 = 36.54 grams;