问题 选择题

航天飞机用的铝粉与高氯酸铵(NH4ClO4)的混合物为固体燃料,点燃时铝粉氧化放热引发高氯酸铵反应,其方程式可表示为:2NH4ClO4

  △  
.
 
 N2↑+4H2O+Cl2↑+2O2↑+Q,下列对此反应叙述中错误的是(  )

A.反应属于分解反应

B.上述反应瞬间产生大量高温气体推动航天飞机飞行

C.反应从能量变化上说,主要是化学能转变为热能和动能

D.在反应中高氯酸铵只起氧化剂作用

答案

A.由一种反应物发生化学反应后生成两种或两种以上的物质的反应为分解反应,反应物高氯酸铵为一种物质,产物为N2、H2O、Cl2、O2↑四种物质,符合定义,故A正确;

B.2NH4ClO4

  △  
.
 
N2↑+4H2O+Cl2↑+2O2↑+Q,+Q表示放热,故B正确.

C.航天飞机用的铝粉与高氯酸铵(NH4ClO4)的混合物为固体燃料,燃料反应为放热反应,反应从能量变化上说,主要是化学能转变为热能和动能,故C正确;

D.2NH4ClO4

  △  
.
 
 N2↑+4H2O+Cl2↑+2O2↑+Q,2molNH4ClO4参加反应,2mol+7价Cl变成0价的1mol Cl2转移14 mol电子,NH4ClO4中氮、氧元素被氧化,氯元素被还原,高氯酸铵既是氧化剂,又是还原剂.故D错误;

故选D.

单项选择题 A1型题
阅读理解

三、阅读(共两节,满分40分)

第一节:阅读下面短文,从每题所给的A、B、C、D四个选项中,选出最佳选项,并把答案写在答题卷上。(共15小题,每小题2分,满分30分)

A

Some people have the feeling that nothing can be done about their poor reading ability. They feel hopeless about it. Can you learn to read better, or must you agree that nothing can be done about it?

To be sure, people are different. You cannot expect to do everything as well as certain other people

do. If all the students in a class tried out for basketball, some would be very good players; others would be very poor; and many would be in between. But even the very poor players can become much better players if they are guided in the right way, and with plenty of practice. It is the same with reading. Some seem to enjoy reading and to read well without any special help. Others find reading a slow and tiring job. In between, there are all degrees of reading ability.

Many experiments have shown that just about every poor reader can improve his reading ability. In these experiments, the poor readers were given tests of reading ability. After some of the causes of their reading were discovered, they were given special instruction and practice in reading. After a few months, another test of the same kind was given. In nearly all cases, these people had raised their reading scores.

41.   With the example of basketball players, the author shows ________.

A. why certain people are poor readers        B. that there are differences in people’s abilities

C. why some people are good basketball players

D. that good basketball players can be good readers

42.   To improve their reading ability, people should ________.

A. work long and hard                               B. take different forms of tests

C. have special help and practice                 D. try different reading materials

43.   The experiments mentioned in the text show that ________.

A. good readers seem to enjoy reading        

B. almost all poor readers can make progress

C. causes of poor reading were difficult to find out

D. tests help people improve their reading ability

44.   What does the underlined sentence “many would be in between” mean?

A. It means that many are the best basket players.

B. It means that many are the worst basket players.

C. It means that many are standing in the middle of the line.

D. It means that there are several levels of players in many students.

45.   What’s the purpose of the author’s writing this passage?

A. To encourage people to improve their reading ability.

B. To suggest that readers should do practice only in reading.

C. To tell us that readers can’t improve their reading ability without special help.

D. To tell us that to be a good reader, one should be guided in the right way.