(0.2*0.2+0.5*0.1)/0.3=0.3mol/L质量分数=溶质质量/溶液质量=0.3*(1+35.5)/1004=1.09%
(0.2*0.2+0.1*0.5)/0.3=0.3mol/L 0.3*0.3*36.5/(1.004*300)=1.09%