Ответ:

Mr (Na2CO3) = 2Ar (Na) + Ar (C) + 3Ar (O) = 2 × (23) + 12 + 3 × (16) = 106

Mr (Fe2(SO4)3) = 2Ar (Fe) + 3Ar (S) +12Ar (O) = 110 + 96 + 192 = 398.

Mr (Cu( OH)2) = Ar (Cu) + 2Ar (O) + 2Ar (H) = 63 + 32 + 2 = 97.

Mr (Al2O3) = 2Ar (Al) + 3Ar (O) = 54 + 48 = 102.

Mr (Ca(ClO4)2 = Ar (Ca) + 2Ar (Cl) + 6Ar (O) = 40 + 70 + 96 = 206.

Mr (CuSO4 * 5H2O) = Mr (CuSO4) + 5Mr(H2O):

Mr(CuSO4) = Ar (Cu) + Ar (S) + 4Ar (O) = 63 + 32 + 64 = 159

5Mr(H2O) = 10Ar(H) + 5Ar (O) = 10 + 80 = 90.

Тогда Mr (CuSO4 * 5H2O) = 90 + 159 = 249.