Массовую долю серы: а) Na2So4 Mr (Na2So4) = w(S) = б) SOз Mr (SOз) = w (S) = в) CuS Mr (CuS) = w(S) = г) H2SOз Mr (Na2SOз) w (S) =
А)М(Na2SO4)=23*2+32*1+16*4=142 W(S)32:142*100%=22% б)M(SO3)32*1+16*3=80 W(S)= 32:80*100%=40% в)M(CuS)=64*1+32*1=96 W(S)=32:96*100%=33% г)M(H2SO4)1*2+32*1+16*3=82 W(S)32:82*100%=39%