Calculate the mass of the salt that forms when 22.4 g of calcium oxide reacts with phosphorus (V) oxide.

Reaction equation: 3CaO + P2O5 = Ca3 (PO4) 2
Let us find the amount of calcium oxide substance n = m / M = 22.4 g / 56 g / mol = 0.4 mol.
According to the reaction, 1 mol of salt is formed from 3 mol of calcium oxide, which means 0.4 / 3 = n (salt) / 1. Hence n (salt) = 0.4 / 3 = 0.13 mol. Let’s find the mass of this salt m = n * M = 0.13 mol * 310 g / mol = 40.3 g (M is the molar mass, determined by the periodic table).
Answer: the mass of salt is 40.3 g.