问题 选择题

下列关于化学能与电能相互转化的说法正确的是

A.在原电池中,化学能转变为电能,电子沿导线由正极流向负极

B.双液原电池通过盐桥连接,KCl盐桥中K+朝正极定向迁移

C.在电解池中,与电源负极相连的电极称为阳极,溶液中阴离子朝阳极定向迁移

D.电解氯化铜溶液,在阴极上产生的气体能使湿润的KI-淀粉试纸变蓝

答案

答案:B

题目分析:A、原电池为化学能转化为电能的装置,电子由负极流向正极,故A错误;B、原电池中阳离子向正极移动,则双液原电池中两个隔离的半电池通过盐桥连接,KCl盐桥中K+朝正极定向迁移,故B正确;C、在电解池中,与电源负极相连的电极称为阴极,电解池的阴极发生还原反应,故C错误;D、电解氯化铜溶液,阴极是铜离子放电析出铜。阳极上氯离子放电,生成氯气,氯气具有强氧化性,能把碘化钾氧化生成单质碘,所以在阳极上产生的气体能使湿润的KI-淀粉试纸变蓝,故D错误,答案选B。

阅读理解

     West Virginia-Public schools are using a dance video game to help get students in shape. In these

schools, students are often told to turn off their video games and get some exercise. The schools have

found a new way for their students to work out while playing a new video game. West Virginia is one

of the heaviest states in the country. About half of its fifthgraders are considered to be overweight, and

their parents are worried about that. To get them moving on a healthier path, the state's public schools

are using a video game called "Dance Revolution".

     To use the game, players should stand on a special mat in front of a TV screen. Following arrows

on the screen, players must move their feet to the specific symbols on the mat. Players must move

quickly, touching symbols on the mat at just the right time. With each song, they get more exercise.

     "If we can get children to change their behavior at a young age, they will hopefully grow up to be

healthy and active adults," said Carl Callison of Mountain State Blue Cross, a health care company.

West Virginia is ranked among the top three heaviest states. About a third of West Virginians are

considered to be  obese (肥胖的). Even more are considered to be overweight. Extra weight can lead

to serious health problems such as high blood pressure, diabetes (糖尿病), some cancers, and many

other health issues.

     "One out of three children born in West Virginia today will have diabetes by the time they grow up,"

said Nidia Henderson, a manager for the public employees' insurance program. "That's a terrible thing

and not acceptable."

     All of West Virginia's 157 middle schools are using the video game. School officials hope that all

public schools in the state will use the game within the next three years. However, officials emphasize

that the game is not meant to substitute physical education and health classes. The game will be part of

physical education classes and afterschool programs.

1. Why do public schools in West Virginia develop "Dance Revolution" ?

A. Because most of the students don't like dancing.

B. Because it can help students get a better shape.

C. Because losing weight is necessary to students.

D. Because it can make students' activities colorful.

2. The second paragraph mainly talks about________.

A. how to get more exercise

B. what are needed in the game

C. how to play a dance video game

D. who can practise the game

3. According to the text, which of the following is NOT true?

A. About one person in three West Virginians is overweight.

B. Overweight may cause a lot of diseases.

C. The problem of students' overweight has been realized.

D. There are only 157 middle schools in West Virginia.

4. The underlined word "substitute" in the last paragraph means "________".

A. replace  

B. change  

C. practise  

D. stop

5. Which is the best title for the text?

A. The Problem of Overweight

B. Dancing for Health

C. Overweight in West Virginia

D. A Dance Video Game

单项选择题