Mr(K₃PO₄) = 39 * 3 + 31 + 16 * 4 = 212 Mr(Ca₃(PO₄)₂) = 40 * 3 + (31 + 16 * 4) * 2 = 310 Mr(NaNO₃) = 23 + 14 + 16 * 3 = 85