Mr[CuSO4] = Ar[Cu] + Ar[S] + Ar[O] * 4 = 63.546 + 32.065 + 15.9994 * 4 = 159.6086 = 160
Mr[BaCO3] = Ar[Ba] + Ar[C] + Ar[O] * 3 = 137.327 + 12.0107 + 15.9994 * 3 = 197.3359 = 197
Mr[Fe2S3] = Ar[Fe] * 2 + Ar[S] * 3 = 55.845 * 2 + 32.065 * 3 = 207.885 = 208
Mr[Al(OH)3] = Ar[Al] + Ar[O] * 3 + Ar[H] * 3 = 26.9815386 + 15.9994 * 3 + 1.00794 * 3 = 78.0035586 = 78
Объяснение:
