问题 选择题

根据下图所示的溶解度曲线,判断下列说法中正确的是

A.甲物质的溶解度小于乙物质的溶解度

B.t2℃时,甲物质的饱和溶液和乙物质的饱和溶液中含有溶质的质量相等

C.将t3℃时的甲、乙两物质的饱和溶液降温到t2℃时析出晶体的质量甲大于乙

D.当甲物质中混有少量乙物质时,可采用降温结晶的方法提纯甲

答案

答案:D

A、温度低于t2℃时甲的溶解度小于乙的溶解度;温度为t2℃时二者的溶解度相等;温度高于t2℃时甲的溶解度大于乙的溶解度.故说法不正确

B、溶液的质量部确定,不能比较溶质的质量相等,故错误

C、溶液的质量部确定,不能比较,故错误

D、甲的溶解度随温度降低而减小且受温度影响较大所以冷却热饱和溶液会大量结晶析出;但乙的溶解度受温度影响较小,冷却热饱和溶液不会析出或析出极少的晶体;所以当甲物质中混有少量乙物质时,可采用冷却热饱和溶液的方法提纯甲.故说法正确.

故选D

阅读理解

阅读理解。

     Two Chinese farmers sang "in the spring" in their small room after drinking in a late August evening in

Beijing. A friend put their song on the Internet. And soon they became stars around China.

     Wang Xu, 44, is from Henan, and Liu Gang, 29, is from Heilongjiang. They are among the millions of

farmers who have gone to the cities to work.

     "Although nobody pays attention to the music, I am singing happily, on streets, under bridges or in wild

country, with no credit card, no girlfriend or a home with hot water, but only a guitar." They sing, "It is just

like the life we live now." Wang said, "We are poor farmers, and you know people won't care about us."

     Their song is loved by millions of Chinese, including the people who are also from the countryside. Many

people said they cried after listening to the song.

     Wang came to Beijing in 2000 and has tried many jobs. Each month after he paid 600 yuan for the house

and bought food, there was little money left. "I love music, and also want to make more money." Wang said.

"I never dreamed of standing on such a big stage."

     Liu came to Beijing in 2002. "I wanted to try my luck in the big city." He said. And now their dreams of

music have come true. They are really the luckiest of all the farmers in China.

1. Where is Liu Gang from? 

    _______________________________________

2. Have their dreams of music come true? 

    _______________________________________

3. When was Wang Xu born? 

    _______________________________________

4. Why did Liu Gang come to Beijing in 2002? 

    _______________________________________

5. What do you think of the two farmer singers? 

    _______________________________________

单项选择题