1、溶质质量20*0.98+30*0.88=46g,总质量20+30=50g,分数=46/50=92%
2、物质的量=46/98=0.47mol,体积为50/1.75=28.57ml=0.02857L,c=0.47/0.02857=16.5mol/L
3、标况下,112L为5mol
500ml含硫酸8.25mol
Zn+2H2SO4=ZnSO4+SO2+2H2O
Zn+H2SO4=ZnSO4+H2
设SO2 xmol,H2 (5-x )mol
2x+5-x=8.25
x=3.25mol
平均摩尔量=总质量/总物质量=(3.25*64+2*1.75)/5=42.3g/mol