问题 选择题

关于溶液的下列说法正确的是(   )

A.c(H):c(OH)=1:10-2的溶液中K、Ba2、ClO、CO32一定能大量存在

B.水电离出来的c(H)=10-13mol/L的溶液中K、Cl、NO3、I一定能大量存在

C.往0.1mol/LCH3COOH溶液中通人少量HCl,醋酸的电离平衡向逆反应方向移动,且溶液中增大

D.等物质的量浓度的下列溶液:①H2CO3②Na2CO3③NaHCO3④(NH4)2CO3中c(CO32)的大小关系为:②>④>③>①

答案

答案:D

题目分析:A、c(H):c(OH)=1:10-2的溶液显酸性,故与CO32不能共存;B、由水电离产生的H+浓度为1×10-13mol•L-1的溶液,溶液为酸或碱溶液,酸性溶液中H+、NO3-、I发生氧化还原反应,则不能共存;C、温度不变,电离常数不变;D.等物质的量浓度的下列溶液:①H2CO3②Na2CO3③NaHCO3④(NH4)2CO3中c(CO32)的大小关系为:②>④>③>①。

阅读理解

In the early 1990s,the word” Internet” was strange to most people. But today, Internet has become a useful tool for people all over the world. Maybe Internet has been the greatest invention in the field of communication in the history of mankind(人类).

Communicating with others on the Internet is much faster. We can chat with a person who is sitting in the other part of the world. We can e-mail our friends and they can read the e-mails within a minute. Giving all kinds of information is probably the biggest advantage of the Internet. We can use search engines to find the information we need. Just type in a keyword or keywords and the search engine will give us a list of suitable websites to look at.

We can enjoy a lot on the Internet by downloading games, visiting chat rooms or surfing (浏览)websites. There are some games for free. We can meet new and interesting people in the chat now. We can also listen to music and see films.

Now ,there is a lot of service on the Internet such as online banking ,job finding and ticket buying. We can also do shopping and find nearly all kinds of goods. Sometimes we can find something that is quite good but very cheap.

小题1:How many main advantages of the Internet are talked about in the        passage?

A.Three.

B.Four.

C.Five.

D.Six.小题2:What fact doesn’t the passage provide?

A.We can find almost anything we want to know on the Internet.

B.Some games on the Internet are free.

C.We can buy most things we need on the Internet.

D.Goods on the Internet are more expensive than those in real shops.小题3:Which title best gives the main idea of the passage?

A.Online Shopping

B.Exchanging Information on the Internet

C.The Advantages of the Internet

D.Surfing the Websites on the Internet

问答题