How many grams of phosphoric acid can be obtained by dissolving 7.1 g of phosphorus oxide in water?

Let’s calculate the chemical amount of a substance in phosphorus oxide weighing 7.1 grams.

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

N P2O5 = 7.1 / 142 = 0.05 mol;

The phosphorus oxide molecule contains 2 phosphorus atoms, and the phosphoric acid molecule contains 1 phosphorus atom. Therefore, from 0.05 mol of phosphorus oxide, 0.05 x 2 = 0.1 mol of acid can be obtained.

Let’s calculate its weight.

To do this, we multiply the amount of the substance by its molar weight.

M H3PO4 = 3 + 31 + 16 x 4 = 98 grams / mol;

m Н3РО4 = 0.1 x 98 = 9.8 grams.