Mr(Na2S) = 23*2 + 32 = 78
W(Na) = Ar(Na) * n / Mr(Na2S) *100% = 23 *2 / 78 *100% =59%
W(S) = Ar(S) * n / Mr(Na2S) *100% = 32 *1 / 78 *100% = 41%
Mr(Na2SO3) = 23*2 + 32 = 16*3 = 126
W(Na) = Ar(Na) *n / Mr(Na2SO3) *100% = 23*2 / 126 *100% = 36,5%
W(S) = Ar(S) * n / Mr(Na2SO3) *100% = 32 *1 / 126 *100% = 25%
W(O) = Ar(O) * n / Mr(Na2SO3) *100% = 16 *3 / 126 *100% = 38%