问题 选择题

已知铅蓄电池放电时发生如下反应:负极:Pb+SO42-2e=PbSO4

正极:PbO2 + 4H+ + SO42+ 2e= PbSO4 + 2H2O。实验室用铅蓄电池作电源,用惰性电极电解CuSO4溶液,当阴极析出2.4g铜时,铅蓄电池内消耗H2SO4物质的量至少是

A.0.050mol

B.0.075mol

C.0.20mol

D.0.40mol

答案

答案:B

析出2.4gCu,即0.0375molCu,转移电子数为0.075mol,Pb+PbO2+2H2SO4=2PbSO4得,消耗的H2SO4物质的量至少是0.075mol

阅读理解

阅读理解。

     When you see the girl for the first time, you may think she is a boy. She is very outgoing (外向). Who is

she? Wang Meng, the Chinese top skater.

     On the evening of February 26th, 2010, Wang Meng first got to the finishing line in 1 minute and 29.213

seconds in the women's 1000 meters short track speed skating final (短道速滑决赛) at the Vancouer Olympic

Winter Games (温哥华冬奥会). After she succeeded in the 500-meter and 3000-meter races, she won her

third gold medal this time. With this one China won four gold medals in the women's short track speed skating.

That helped China first win the team gold medal in Winter Olympics history.

     Just before the final race Wang Meng caught a bad cold and coughed terribly. With the words of "You can,

you can do!" she won at last. She said, "I really feel these three gold medals belong to my team, to China. It

was with the help of my team that I won the prize."

     Though Wang Meng is only twenty-four, she has been the most successful Chinese skater. Chinese are

proud of her and her team. We hope she will be faster in Sochi Olympics in 2014.

1. China won ____ gold medals in the women's short track speed skating.

A. 2

B. 3

C. 4

D. 5

2. It took Wang Meng 1 minutes and 29.213 seconds to finish the ____ short track speed skating final.

A. women's 1000

B. men's 1000

C. women's 500

D. men's 500

3. In Wang Meng's opinion, ____ made her win the prize at last.

A. a strong body

B. a bad cold

C. her team's help

D. much exercise

4. Which of the following is NOT true according to the passage?

A. Wang Meng is very outgoing like a boy.

B. Wang Meng is the most successful Chinese skater.

C. Chinese people are proud of Wang Meng and her team.

D. China has got the team gold medal twice in Winter Olympics history.

问答题 简答题