问题 问答题

为了检验含二氧化碳的废气中混有一氧化碳,用下图所示装置进行实验.其中,A和E中的液体是氢氧化钠溶液;B和D中的液体是澄清的石灰水,试回答:

(1)当观察到______时,说明混合气体中一定混有一氧化碳.

(2)装置C中发生反应的化学方程式是______.

(3)装置B的作用是______;装置E的作用是______,该装置中发生反应的化学方程式是______.

答案

(1)一氧化碳具有还原性,所以能使红色固体逐渐变为黑色,同时生成二氧化碳,所以当观察到C中红色固体变为黑色,D中澄清石灰水变浑浊时,说明混合气体中一定混有一氧化碳.

(2)一氧化碳具有还原性,所以能使红色固体逐渐变为黑色,装置C中发生反应的化学方程式是3CO+Fe2O3

 高温 
.
 
2Fe+3CO2

(3)A装置用来除去原气体中含有二氧化碳,B中的澄清石灰水用来检验二氧化碳是否除尽.E中的氢氧化钠溶液是用来除去二氧化碳并收集一氧化碳;氢氧化钠溶液与二氧化碳反应,生成碳酸钙沉淀和水,化学方程式是:Ca(OH)2+CO2═CaCO3↓+H2O.

故答案为:

(1)C中红色固体变为黑色,D中澄清石灰水变浑浊.

(2)3CO+Fe2O3

 高温 
.
 
2Fe+3CO2

(3)检验二氧化碳已除净;除去二氧化碳并收集一氧化碳;Ca(OH)2+CO2═CaCO3↓+H2O.

阅读理解

How many people have I met who have told me about the book they have been planning to write but have never yet found the time ? Far too many.

This is Life, all right, but we do treat it like a rehearsal (排演) and, unhappily, we do miss so many of its best moments.

We take jobs to stay alive and provide homes for our families always making ourselves believe that this style of life is merely a temporary state of affairs along the road to what we really want to do. Then, at 60 or 65, we are suddenly presented with a clock and several grandchildren and we look back and realize that all those years waiting for Real Life to come along were in fact real life.

In  America they have a saying much laughed at by the English:“Have a nice day” they speak slowly and seriously in their shops, hotels and sandwich bars. I think it is a wonderful phrase, reminding us, in effect, to enjoy the moment: to value this very day.

How often do we say to ourselves, "I'll take up horse-riding (or golf, or sailing) as soon as I get a higher position," only to do none of those things when I do get the higher position.

When I first became a reporter I knew a man who gave up a very well paid respectable job at the Daily Telegraph to go and edit a small weekly newspaper. At the time I was astonished by what appeared to me to be his completely abnormal (反常的) mental state. How could anyone turn his back on Fleet Street in central London for a small local area?I wanted to know.

Now I am a little older and possibly wiser, I see the sense in it. In Fleet Street the man was under continual pressure. He lived in an unattractive London suburb and he spent much of his life sitting on Southern Region trains.

小题1:

The first paragraph of the passage tells us that          .

A.we always try to find some time to write a book

B.we always make plans but seldom fulfill them

C.we always enjoy many of life's best moments

D.we always do what we really want to do小题2:

The underlined phrase "turn his back on" (paragraph 6) most probably means         .

A.leave for

B.return to

C.give up

D.rely on小题3:

The man ( paragraph 6) left his first job partly because he was           .

A.in an abnormal mental state

B.under too much pressure

C.not well paid

D.not respected小题4:

What is probably the best title for the passage?

A.Provide Homes For Our Family

B.Take Up Horse-riding

C.Value This Very Day

D.Stay Alive

单项选择题