Ответ:

Объяснение:

Mr(K2CO3) = 39*2 + 12 + 16*3 = 138

W(K) = Ar(K) *n / Mr(K2CO3)  *100% = 39*2 / 138  *100% = 56%

Mr(K3PO4) = 39*3 + 31 + 16*4 = 212

W(K) = Ar(K) *n / Mr(K3PO4)  *100% = 39*3 / 212  *100% =55%