问题 选择题

下表记录了物质X的溶液分别加入到另外三种物质的溶液中产生的现象.则物质X的化学式可能是(  )

氢氧化钠碳酸钠石蕊
物质X无明显现象产生气泡溶液变红

A.Ca(OH)2

B.CuSO4

C.HCl

D.BaCl2

答案

A、如物质X是氢氧化钙时:与氢氧化钠不反应没现象;与碳酸钠能反应生成的是白色沉淀碳酸钙,无气泡产生.故 A不正确.

    B、如物质X是硫酸铜时:与氢氧化钠反应能生成蓝色沉淀氢氧化铜,有明显现象,故 B不正确.

    C、如物质X是盐酸溶液时:与氢氧化钠反应但没现象,符合题意;与碳酸钠能反应生成气体二氧化碳,有气泡生成,也符合题意;与石蕊试液作用溶液变红.故 C正确.

    D、如物质X是氯化钡时:与氢氧化钠不反应没现象,符合题意;与碳酸钠能反应生成的是白色沉淀碳酸钡,无气泡产生.故 D不正确.

故选 C

阅读理解

阅读理解。    

     The best way of learning a language is using it. The best way of learning English is talking in English as

much as possible. Sometimes you'll get your words mixed up(混合)and people will not understand

you, sometimes people will say things too quickly and you can't understand them. But if you keep your

sense of humour(幽默感),you can always have a good laugh at the mistakes you make. Don't be

unhappy if people seem to be laughing at your mistakes. It's better for people to laugh at your mistakes

than to be angry with you, because they don't understand what you are saying. The most important thing

for learning English is: “Don't be afraid of making mistakes because everyone makes mistakes.”  

1. The writer things that the best way for you to learn a language is       .    

A. writer

B. using it    

C. listening

D. learning grammar       

2. What should you do in learning English?   

A. Be careful not to make any mistakes.    

B. Write as quickly as you can.

C. Speak English as much as you can.    

D. Laugh more often. 

3. When people laugh at your mistakes , you should       

A. not care

B. be happy    

C. feel worried

D. be unhappy  

4. When you make a mistakes , you should       .    

A. keep quite

B. get angry    

C. be kind

D. keep your sense of humour    

5. The story tells us : “      .”  

A. Only foolish(愚蠢的)people make mistakes    

B. Few people make mistakes    

C. People never make mistakes    

D. There is no one who doesn't make mistakes

单项选择题 共用题干题