Question

Calculate the mass percent of calcium, phosphorus and oxygen in calcium phosphate Ca₃(PO₄)₂.

Answer 1

Mass percent of calcium

Mass percent of phosphorus

Mass percent of oxygen

Answer 2

Ca3( PO4)2

atomic mass of calcium ( Ca) = 40 g/mol
atomic mass of phosphorus ( P) = 31 g/mol
atomic mass of Oxygen ( O) = 16 g/mol
molecular mass of C3(PO4)2 = 3 × 40 + 2× (31+ 64) = 120 + 2 × 95 = 120 + 190
= 310 g/mol

now,

% of Ca in Ca3(PO4)2 = 3×40/310 × 100
= 1200/31 % = 38.7 %

% of P in Ca3(PO4)2 = 2×31/310 × 100
= 20 %

% of O in Ca3(PO4)2 = 8 × 16/310 × 100
= 1280/31 = 41.3 %