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问题 填空题

在化学反应中，物质所含元素的化合价发生了变化的反应就是氧化还原反应． 例：2Na+Cl2═2NaCl，反应前后，Na、Cl的化合价发生了变化，该反应是氧化还原反应．

（1）根据化合价是否变化分析，下列反应不属于氧化还原反应的是（填序号）______．

A.2Mg+O2

 点燃 
.
 
2MgO；

B．CaO+H2O═Ca（OH）2

C.2KClO3

MnO2
.
△
2KCl+3O2↑    

D．H2+CuO

  △  
.
 
Cu+H2O

（2）含有高价态的化合物，通常具有氧化性，如在氯化铁溶液中，氯化铁能将单质铜氧化成氯化铜，自身被还原成氯化亚铁．试回答：

①该反应的化学方程式可表示为______．

②向上述反应后的溶液中加入适量的锌粉反应后过滤，向过滤后得到的固体物质上加稀盐酸有气泡产生，则滤纸上一定含有的固体是（写化学式）______，滤液中的溶质一定含有的是______．

答案

（1）因为物质所含元素的化合价发生变化的反应就是氧化还原反应，而有单质生成或参与的反应中元素的化合价往往存在变化，分析四个反应的特点可知在四个反应中ACD三个反应符合该特征，是氧化还原反应，B选项中各种元素的化合价不变，不是氧化还原反应；

（2）①由氯化铁溶液能和单质铜反应生成两种氯化物的信息可知产物为氯化亚铁和氯化铜．

②利用金属活动性可知锌的活动性既大于铁又大于铜，所以可以置换出来溶液中的铜离子和铁离子，但反应的顺序是先去置换活动性最弱的铜离子，当铜离子被全部还原后才去置换溶液中的铁离子，适量的锌粉说明锌的量不固定，则可说明一定含有的固体是铜，固体物质上加稀盐酸有气泡产生，说明固体中含有能遇酸生成气体的金属，则可判断金属固体中一定有铁，含不含锌由于其量不固定，所以无法确定，从反应过程看滤液中一定有氯化锌．

故答案为：

（1）B；

（2）①2FeCl3+Cu═2FeCl2+CuCl2；

②Cu、Fe；ZnCl2．

选择题

My father started to ________ coffee instead of tea when he was working in Australia.  [ ]

A. used to drink

B. used to drinking  

C. get used to drinking

D. get used to drink
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问答题

To get help, Internet addicts tired of their square-eyed, keyboard tapping ways need look no further than the Web for counseling. There is now an online counseling service at www. relate, org. nz for Internet obsessives. Just e-mail the details of your Internet-induced crisis and help comes direct to your inbox. (46)The new breed of cybertherapists see nothing strange about offering help through the very medium that is swallowing their clients’ free time and splitting their marriages.
Getting hooked on the Internet isn’t confined to a few computer nerds. It’s on the rise everywhere—and women are the most likely addicts. The old stereotypical addict was a young man who spent hours playing games, downloading software or reading messages on newsgroups. (47)Yet, the new image is of a young woman who fritters away hours e-mailing friends, buying books and CDs online, talking in chatrooms and looking for information for next year’s holiday.
Ingrid Parker, once a slave to Internet chatrooms, found her experiences so devastating that she wrote a book to help other addicts break the habit. (48) Her computer dream turned to nightmare when she sold up and moved to be with her cyberpal (who had just left his wife), only to be told a week later that the couple were getting back together. The heart-breaking turn of events gave her the motivation to control her addiction—and write the book Caught in the Web.
For Ingrid Parker, anyone who is married or in a sound relationship should not really be spending hours talking to someone else and ignoring their nearest and dearest. (49)While Parker provided her own therapy by putting her experiences down on paper, she recommends others take up the online counseling offer, or log off from the Worldwide Web gradually.
She said, "It’s like smoking. It’s not a good idea to suddenly go cold turkey. People often e mail me about the problem and I tell them to gradually wean themselves off and not to switch to a scheme where you pay per hour for online time. (50)If they break their resolution, all they end up with then is the same old problem plus money difficulties for the long hours they have spent logged in to the Internet. "
Of course, the Internet is definitely addictive but if you can keep it in control it has advantages, too. Using it can be a steep learning curve so it helps you become very quick at learning. Also there is a huge demand for people in the field of Information Technology (IT) and hours on the Internet are great training.
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