Mr[NaCl] = Ar[Cl] + Ar[Na] = 35 + 23 = 58
Mr[AgNO3] = Ar[Ag] + Ar[N] + Ar[O] * 3 = 108 + 14 + 16 * 3 = 170
Mr[BaCl2] = Ar[Ba] + Ar[Cl] * 2 = 137 + 35 * 2 = 208
Mr[Na2SO4] = Ar[Na] * 2 + Ar[O] * 4 + Ar[S] = 23 * 2 + 16 * 4 + 32 = 142
Объяснение:
