Ответ:

Mr[H2CO3] = Ar[H] * 2 + Ar[C] + Ar[O] * 3 = 1.00794 * 2 + 12.0107 + 15.9994 * 3 = 62.02478 = 62

Mr[Mg(NO2)2] = Ar[Mg] + Ar[N] * 2 + Ar[O] * 4 = 24.305 + 14.0067 * 2 + 15.9994 * 4 = 116.316 = 116

Mr[Ba(OH)2] = Ar[H] * 2 + Ar[Ba] + Ar[O] * 2 = 1.00794 * 2 + 137.327 + 15.9994 * 2 = 171.34168 = 171

Mr[(NH4)3PO4] = Ar[H] * 12 + Ar[N] * 3 + Ar[O] * 4 + Ar[P] = 1.00794 * 12 + 14.0067 * 3 + 15.9994 * 4 + 30.973762 = 149.086742 = 149

Объяснение: