问题 完形填空
完形填空。

      Once upon a time, there were two men. One was hard-working and had a lot of   1   and perseverance
(坚定不移), while the other was   2   and never did any work. One night, they decided to have a competition
between them. The contest was simple: the   3   person to see daylight would be the winner, and the winner
would   4   a prize. Both men agree to do it, and the competition started.
      The hard-working man immediately   5   and ran towards the west after the sun, while the lazy man just
sat there and   6  . The hard-working man, looking at the competitor,   7   at his foolishness and kept going
at his quick pace. Running through the jungles, swimming   8   the rivers and seas, and he kept running and
running,   9   that he would reach his goal sooner or later. Meanwhile, the lazy man was still sleeping.
      The hard-working man had been  10  for 6 hours already, and he was surprised that he still had not  11  
daylight. Thinking it would be just around the corner, he  12  on running until he finally came back to where
he started, 24 hours  13 . Upon arriving, he saw the lazy man seated there, smiling and waiting for him,
holding the  14   he earned.
      The hard-working man was  15  how this lazy man could earn it-he hadn't done anything at all! Then the
lazy man said, "You are  16  a persevering and patient man, but you were running towards the  17 , running
after the sun that kept moving away from your  18  whereas I just waited for the sun to come to me. You
were lucky. If I had decided to  19  you and not to tell you, you would be continuing this pursuit till your
death." The hard-working man knew in his heart that the lazy man was right.
      Sometimes, perseverance can  20  you from the truth that what you are doing is wrong.

( )1. A. hobbies             
( )2. A. lazy                
( )3. A. last                
( )4. A. accept             
( )5. A. set in              
( )6. A. worked             
( )7. A. laughed            
( )8. A. across               
( )9. A. representing        
( )10. A. swimming           
( )11. A. admired             
( )12. A. commented          
( )13. A. before              
( )14. A. money               
( )15. A. believing           
( )16. A. true                
( )17. A. west                
( )18. A. ears               
( )19. A. hide from         
( )20. A. make                
B. ideas       
B. patient      
B. first      
B. keep        
B. set aside   
B. drank      
B. glared      
B. through     
B. believing    
B. jumping     
B. invented     
B. carried    
B. later      
B. medal      
B. recognizing        
B. indeed      
B. east        
B. hands       
B. learn from     
B. let           
C. patience          
C. kind-hearted      
C. second            
C. win               
C. set up            
C. slept             
C. stared            
C. over              
C. emphasizing       
C. resting           
C. found             
C. figured           
C. next              
C. prize             
C. discussing        
C. certain           
C. north             
C. sight            
C. keep from         
C. blind             
D. money           
D. hard-working    
D. only          
D. defeat          
D. set out         
D. played          
D. looked        
D. past            
D. complaining     
D. running       
D. realized        
D. depended        
D. further         
D. gold            
D. wondering                        
D. hardly          
D. south           
D. mind            
D. come from       
D. protect       
答案

1-5: CABCD  6-10: CAABD  11-15: CBBCD  16-20: BACBC

问答题
实验题

(7分)学习了CO2的有关知识之后,同学们查阅资料发现Mg能在CO2中燃烧:

2Mg + CO2=2MgO + C,所以镁着火不能用CO2来灭火。但没有找到有关钠能否与CO2反应的介绍。于是同学们展开钠着火能否用CO2来灭火的探究。

【提出猜想】钠能发生类似于CO2与镁的反应,可能的化学方程式为                    

【实验】将燃着的钠伸入装有CO2的集气瓶中,钠能在CO2中继续燃烧。

进一步【查阅资料】得知:

①Na2O是白色固体,能与CO2反应生成Na2CO3,与H2O反应生成NaOH。

②室温下部分酸碱盐的溶解性表(氯化钡溶液呈中性)

 Ba2+Ca2+Na+Cu2+
OH
CO32-
Cl-
 

基于以上资料,同学们认为钠在CO2中燃烧的产物应该与Mg在CO2中燃烧的产物情况有所不同,并对产物提出了以下几种猜想:

① Na2O、C       ②           、C     ③ NaOH、C      ④ Na2O、Na2CO3、C

通过理论分析,猜想                  (填序号)肯定是错误的。

【验证猜想】(最终猜想④是正确的)

步骤实验操作主要实验现象结论(燃烧产物判断)
(1)取少量产物于试管中,加适量水中,振荡,静止 燃烧产物中肯定有炭
(2)取(1)所得少量上层清液,加入                           
(3)   
 

在步骤(3)中也可以通过加入        试剂的方法进行检验(任写一种与(3)中所加不同种类的试剂)。

【结论】猜想④正确。金属钠着火不能用二氧化碳灭火。