1) Mr(K2CO3) = 39*2 + 12 + 16*3 = 138
W(K)1) Mr(K2CO3) = 39*2 + 12 + 16*3 = 138
W(K) = Ar(K) *n / Mr(K2CO3) *100% = 39*2 / 138 *100% = 56%
W(C) = Ar(C) *n / Mr(K2CO3) *100% = 12*1 / 138 *100% = 9%
W(O) = Ar(O) * n / Mr(K2CO3) *100% = 16*3 / 138 *100% = 35%
2) Mr(MgCl2) = 24 + 35,5*2 = 95
W(Mg) = Ar(Mg) * n / Mr(MgCl2) *100% = 24*1 / 95 *100% = 25%
W(Cl) = Ar(Cl) *n / Mr(MgCl2) *100% = 35,5*2 / 95 * 100% = 75%