Объяснение:
Mr(K2CrO4) = 39*2 +52 +16*4 =194
W(K) = Ar(K) *n / Mr(K2CrO4) *100% = 39*2 / 194 *100% =40%
W(Cr) = Ar(Cr) *n / Mr(K2CrO4) *100% = 52*1 / 194 *100% =27%
W(O) = Ar(O) *n / Mr(K2CrO4) *100% = 16*4 / 194 *100% = 33%
