问题 选择题

在密闭容器中进行反应:H2(g)+Br2(g)2HBr(g) ΔH<0,达到平衡后,欲使颜色加深,应采取的措施是(  )

A.升高温度

B.降低温度

C.增大H2浓度

D.减小压强

答案

答案:A

欲使颜色加深,则Br2的浓度应变大。该反应为放热反应,升温平衡向左移动,Br2的浓度变大,因此颜色加深。增大氢气浓度,平衡向右移动,Br2的浓度减小,颜色变浅。减小压强通过增大容器体积实现,平衡不移动,但Br2的浓度减小,颜色变浅。

完形填空
完形填空。
     When I was about 12, a girl in my class liked to point out my problems. I was too thin; I wasn't a good
student; I talked too much, I was too   1  , and so on. At last, I became very angry and ran to my father.
     He listened to me   2  . Then he asked, "Are these things true or not? Do you know what you are really
like? Go and make a   3   of what she said and find the   4   that are true."
     I did as he told me. To my great   5  , I discovered that about half of the things were true. Some of them
I couldn't change (like being very thin). But there were things I could and wanted to change. For the   6   time,
I got a clear   7   of myself.
     I brought the list back to Dad. He refused to take it. "That's just for you." he said, "You know the truth
about   8   better than anyone else. When people say something that is true about you, you should find it
helpful."
     Our world is full of people who think they know your business. Don't   9   your ears and feel  10 . Listen
to them.
( )1. A. beautiful   
( )2. A. bravely     
( )3. A. joke        
( )4. A. secrets     
( )5. A. surprise    
( )6. A. first       
( )7. A. book        
( )8. A. yourselves  
( )9. A. clean       
( )10. A. hurt       
B. proud      
B. happily    
B. programme    
B. mistakes   
B. interest   
B. second     
B. picture    
B. myself     
B. open     
B. safe     
C. smart     
C. quickly   
C. list      
C. lessons   
C. opinion   
C. next      
C. drawing      
C. herself   
C. close     
C. pretty    
D. rich    
D. quietly 
D. record                        
D. points  
D. fact    
D. last    
D. notice  
D. yourself
D. wash    
D. cheap   
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