Мr(P2O5) = 2Аr(P) + 5Аr(O);
Мr(P2O5) = 2 • 31 + 5 • 16 = 142;
W(P) = 62/142 = 0, 44 = 44 %
W (O) = 80/142 = 0,56 = 56 %
Мr(HNO3) = Аr(H) + Аr(N) + 3Аr(O) ;
Мr(HNO3) = 1 + 14 + 3 • 16 = 63;
W(H) = 1/63 = 0, 016 = 1,6 %
W (N) = 14/63 = 0, 22 = 22 %
W (O) = 48/63 = 0, 76 = 76%
Мr(AsH3) = Аr(As) + 3Аr(H) ;
Мr(AsH3) = 75 + 3 • 1 = 78;
W(As) = 75/78 = 0, 96 = 96 %
W (H) = 3/78 = 0, 038 = 3,8 %