Найти % содержания элемента Ca3(Po4)2
Mr(Ca3(PO4)2) = 3*40+2*31+8*16 = 310 W(Ca) = 120/310= 0.39=39% W(P) = 62/310 = 0.2=20% W(O) = 128/310 = 0.41=41%