问题 实验题

某教师在课堂上用下图所示的装置来验证浓硫酸与铜是否发生反应并探讨反应所产生气体的性质。请回答下列问题:

(1)通过试管乙中发生的            现象说明了铜和浓硫酸发生了化学反应,并且该现象还能说明产生的气体具有     性。

(2)若要收集试管甲中生成的气体,可以采用       收集方法。

①排水取气法    ②向上排空气取气法    ③向下排空气取气法

(3)写出试管甲中所发生反应的化学反应方程式                               

(4)试管乙口部浸有碱液的棉花的作用是                                     

此防范措施也说明产生的气体是           气体(填“酸性”、“中性”或“碱性”)。

答案

(1)品红溶液   漂白性     (2)②

(3)Cu+2H2SO4(浓) CuSO4+SO2↑+2H2O

(4)吸收产生的SO2气体     防止污染环境   酸性

(1)SO2检验漂白性,能使品红溶液褪色,据此可以说明铜和浓硫酸发生了化学反应。

(2)SO2易溶于水,但密度大于空气的,所以可用向上排空气法收集,答案选②。

(3)方程式为Cu+2H2SO4(浓) CuSO4+SO2↑+2H2O。

(4)SO2是一种大气污染物,同时也是一种酸性气体,可用碱液吸收。

单项选择题
完形填空
完形填空。
     Across the street from our home was a school and I would often watch the kids as they played basketball
during the break. I often noticed a small   1   playing with boys. I watched in   2   as she ran circles around the
other kids. She   3   to shoot jump shots just over their heads and into the net. The boys always tried to stop
her but no one could. At other times I saw her playing alone, sometimes until   4  .
     One day I asked her way she   5   so much. She looked   6   in my eyes and without a moment of hesitation
she said, "The only way I can go to   7   is to get a scholarship. I believe that I would get it if I were good
enough at   8  . My Daddy told me if the dream is big enough, the facts don't   9  ." Then with a determined
smile she ran towards the court, I watched her  10  those junior high school years and into high school. Every
week, she led her team to victory.
     One day in her senior year, I saw her sitting in the grass, head  11  in her arms. The coach told her that at
5 feet 5 inches she would  12   never get to play for a top ranked team--much less offered a scholarship-so
she should  13  dreaming about college. I asked her if she had talked to her dad about it yet. She  14   her head
from her hands and told me that her father said those coaches just did not understand the  15  of a dream. He
told her that if she truly wanted a scholarship,  16  could stop her except one thing-her own attitude.
     The next year,  17  she and her team went to the Northern California Championship game, she was seen by
a college coach. She was indeed  18  a scholarship, a full one. She was going to get the college education that
she had  19   and worked toward for all those years. It's  20  : If the dream is big enough, the facts don't count.
( )1. A. boy           
( )2. A. doubt         
( )3. A. managed       
( )4. A. morning       
( )5. A. practised     
( )6. A. slowly        
( )7. A. work          
( )8. A.football       
( )9. A. damage        
( )10. A. past         
( )11. A. buried       
( )12. A. firmly       
( )13. A. stop         
( )14. A. lowered      
( )15. A. effect       
( )16. A. something    
( )17. A. after        
( )18. A. brought      
( )19. A. thought of   
( )20. A. true         
B. girl             
B. shock            
B. tried            
B. noon             
B. suffered        
B. quickly          
B. court             
B. basketball     
B. delay            
B.over             
B. placed          
B. sadly           
B. begin           
B. lifted           
B. power          
B. anything         
B. before         
B. handed           
B. dreamed of     
B. possible      
C. student           
C. wonder            
C. failed          
C. dark               
C. performed        
C. quietly          
C. college            
C. my lessons      
C. count             
C. beyond            
C. hidden           
C. nearly           
C. continue          
C. turned          
C. aim              
C. nobody            
C. as              
C. sent               
C. asked for       
C. proper        
D. teacher                
D. delight                    
D. attempted              
D. dawn                        
D. drilled                   
D. directly               
D. school                     
D. the exams             
D. fail                    
D. through                     
D. dropped                   
D. probably                
D. start                     
D. moved                   
D. advantage                
D. nothing                   
D. once                     
D. offered                  
D. referred to             
D. perfect