Объяснение:
Mr(Na2CO3) = 23*2 + 12+ 16*3 =106
W(Na) = Ar(Na) *n / Mr(Na2CO3) *100% = 23*2 / 106 *100% = 43%
W(C) = Ar(C) *n / Mr(Na2CO3) *100% = 12*1 / 106 *100% = 11%
W(O) = Ar(O) *n / Mr(Na2CO3) *100% = 16*3 / 106 *100% =46%
