在质量分数为0.80的甲醇水溶液中,甲醇的摩尔分数接近于( )
A. 0.3
B. 0.5
C. 0.9
D. 0.7
查看答案
有同温同体积的三杯蔗糖溶液,A杯溶液浓度为1 mol/kg,B杯溶液浓度为1 mol/L,C杯溶液质量分数为10%,已知蔗糖的相对分子质量为180,则各杯中蔗糖的质量( )。
A. C杯多
B杯多
C. A杯多
D. A杯等于B杯
Why has the number of newspaper readers fallen?
When did the decline begin?
How many young Americans read a newspaper today?