Mr(CuSO4) = 63,5 + 32 + 16*4 = 159,5
W(Cu) = Ar(Cu)* n / Mr(CuSO4) *100% = 63,5 *1 / 159,5 *100% = 40%
W(S) = Ar(S) *n / Mr(CuSO4) *100% = 32*1 / 159,5 *100% = 20%
W(O) = Ar(O) * n / Mr(CuSO4) *100% = 16 * 4 / 159,5 *100% = 40%
Mr(Fe2O3) = 56*2 + 16*3 = 160
W(Fe) = Ar(Fe) * n / Mr(Fe2O3) *100% = 56 *2 / 160 *100% = 70%
W(O) = Ar(O) *n / Mr(Fe2O3) *100% = 16*3 / 160 * 100% = 30%
Mr(HNO3) = 1 + 14 + 16*3 = 63
W(H) = Ar(H) *n / Mr(HNO3) *100% = 1 *1 / 63 *100% = 1,6%
W(N) = Ar(N) * n / Mr(HNO3) *100% = 14 *1 / 63 *100% = 22%
W(O) = Ar(O) *n / Mr(HNO3) * 100% = 16 * 3 / 63 *100% = 76%