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%
Mr(Mn(NO3)2) = 55 + 14*2 + 16 * 6 = 179
W(Mn) = Ar(Mn) * n / Mr(Mn(NO3)2 *100% = 55 *1 / 179 *100% =31%
W(N) = Ar(N) * n / Mr(Mn(NO3)2 *100% = 14 *2 / 179 *100% = 16%
W(O) = Ar(O) * n / Mr(Mn(NO3)2 *100% = 16 * 6 / 179 *100% = 54%