Approximately 12 million kilograms of phosphoric acid (H3PO4) are produced annually for fertilizers, detergents, and agents for water treatment. Phosphoric acid can be prepared by heating the mineral fluoroapatite (Ca5(PO4)3F) with sulfuric acid in the presence of water. Ca5(PO4)3F + 5H2SO4 + 10H2O 3H3PO4 + 5CaSO4.2H2O + HF If every kilogram of fluoroapatite yields 4.00E2 g of phosphoric acid, what is the percent yield? I don't get this question!! I tried it several times and keep getting the question incorrect. Please help!