Calculate the mass of phosphoric acid obtained by reacting phosphorus (V) oxide with a mass of 71 g with water.

The reaction for obtaining phosphoric acid from phosphorus oxide is described by the following chemical reaction equation.

P205 + 3H2O = 2H3PO4;

The phosphorus oxide molecule has two phosphorus atoms, and the acid molecule has one phosphorus atom. Therefore, to obtain one mole of acid, half a mole of phosphorus oxide is required.

Let’s find the amount of the substance contained in 71 grams of phosphorus oxide.

Its molar mass is.

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

The amount of the substance will be.

N P2O5 = 71/142 = 0.5 mol;

From this amount, 1 mol of phosphoric acid can be obtained.

Let’s find its mass.

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

m H3PO4 = 1 x 98 = 98 grams;