How much orthophosphoric acid can be obtained from 31 tons of calcium orthophosphate containing 20% impurities?

One molecule of calcium orthophosphate Ca3 (PO4) 2 contains 2 phosphorus atoms. Therefore, from one mole of calcium orthophosphate, 2 moles of phosphoric acid can be obtained.

Find the molar mass of calcium orthophosphate: 40 x 3 + (31 + 16 x 4) x 2 = 310 grams / mol.

Since orthophosphate contains 20% impurities, 31 x (1 – 0.2) = 24.8 tons can participate in the reaction.

Determine the molar amount of orthophosphate: 24.8 tons / 310 grams / mol = 80,000 mol.

Accordingly, from this amount, you can get 80,000 x 2 = 160,000 moles of acid.

The molar mass of orthophosphoric acid H3PO4 = 1 x 3 + 31 + 16 x 4 = 98 grams / mol.

Let’s translate the resulting molar amount into mass: 98 x 160,000 / 1,000,000 = 15.68 tons.