How many grams of calcium phosphate, silicon oxide, coal must be decomposed to obtain 31g of phosphorus.

Let’s write down the reaction
Ca3 (PO4) 2 + 3SiO2 + 5C = 3CaSiO3 + 5CO + 2P
Let us find the amount of phosphorus by the formula n = m / M, where n is the amount of the substance, m is the mass of the substance, M is the molar mass of the substance
n (P) = 31/31 = 1 mol
Find a mass of coal
n (C) = 5 mol
m = n * M
m (C) = 5 * 12 = 60 g
Find the mass of silicon oxide
n (SiO2) = 3 mol
m (SiO2) = 3 * 60 = 180 g
Find the mass of calcium orthophosphate
n (Ca3 (PO4) 2) = 1 mol
m (Ca3 (PO4) 2) = 1 * 310 = 310 g
Answer: m (C) = 60 g, m (SiO2) = 180 g, m (Ca3 (PO4) 2) = 310 g