问题 选择题

下列图像能正确反映对应变化关系的是

答案

答案:A

题目分析:结合具体反应,对应图像分析。

A、向一定量的二氧化锰中加入过氧化氢溶液,过氧化氢在二氧化锰的催化作用下,分解产生水和氧气,由于氧气是生成物,故其质量随反应物过氧化氢的不断加入,会从0开始不断变大,正确;

B、将铁钉加入硫酸铜溶液中,二者发生置换反应生成铜和硫酸亚铁,即Fe+CuSO4="Cu+" FeSO4,其中参加反应的Fe与生成的Cu的质量比为56:64,由此可知,固体的质量随铁钉的加入而变大,图像正好相反,错误;

C、向一定量的大理石中加入足量的稀盐酸,二者反应生成氯化钙、水和二氧化碳,由此可知,固体的质量随盐酸的加入而变小,直至大理石完全反应,但由于其中的杂质不参加反应,故最终固体的质量不可能为0,错误;

D、向一定量的稀盐酸中加入足量的铁粉,二者发生置换反应生成氯化亚铁和氢气,即Fe+2HCl=FeCl2+H2↑,由于氢气是生成物,故其质量随反应物铁粉的不断加入,会从0开始不断变大直至盐酸完全反应不再变化,错误。故选A

点评:此题是一道反应与图象的结合题,解题的关键是能结合反应分析各种量的变化关系,利用反应与图象相结合进行分析探讨,进而作出正确的判断;图象的意义要抓住三点:①抓图象的起点,②抓图象的终点,③抓图象的变化过程。

完形填空
完形填空。
     Recently, I flew to Las Vegas to attend a meeting. As we were about to arrive, the pilot announced with
apology that there would be a slight   1   before setting down. High desert winds had   2   the airport to close
all but one runway. He said that we would be   3   the city for a few minutes waiting to   4  . We were also
told to remain in our seats meanwhile with our seat belts fastened   5   there might be a few bumps (颠簸).
Well, that few minutes turned into about four-five minutes, including a ride that would make a roller coaster
(过山车)   6   by comparison.
     The movement was so fierce that several passengers felt   7   and had to use airsickness bags. As you
might guess, that's not good thing to have happen in a(n)   8   space because it only   9   to increase the
discomfort of the situation.
     About twenty minutes into the adventure,the entire airplane became very  10 . There was now a sense of
anxiety and fear that could be  11  noticed. Every passenger simply held on for dear life…except one. A  12 
 was having a good time! With each bump of the  13 , he would let out a giggle (咯咯的笑) of delight. As I
observed this, I  14  that he didn't know he was supposed to be afraid and worried about his  15  He neither
thought about the past nor about the future. Those are what we grown-ups have learned from  16 . He was
  17  the ride because had not yet been taught to fear it. Having understood this, I took a deep breath and  18 
 back into my seat, pretending I was  19  on a roller coaster. I smiled for the rest of the flight. I even  20  to
giggle once or twice, much to the chagrin (懊恼) of the man sitting next to me holding the airsickness bag.
( )1. A. mistake   
( )2. A. forced    
( )3. A. watching  
( )4. A. arrive    
( )5. A. if        
( )6. A. light     
( )7. A. sick      
( )8. A. empty     
( )9. A. happens   
( )10. A. quiet     
( )11. A. partly    
( )12. A. pilot     
( )13. A. seats     
( )14. A. realized  
( )15. A. health    
( )16. A. teachers  
( )17. A. learning  
( )18. A. sat       
( )19. A. nearly    
( )20. A. attempted 
B. delay      
B. warned     
B. visiting   
B. enter      
B. though     
B. pale       
B. nervous    
B. narrow     
B. continues  
B. hot        
B. gradually 
B. baby       
B. passengers    
B. hoped     
B. safety     
B. books      
B. taking    
B. lay        
B. finally   
B. managed   
C. change      
C. swept       
C. circling    
C. stop        
C. because     
C. easy        
C. angry       
C. secret    
C. fails       
C. dirty      
C. shortly     
C. guard      
C. flight      
C. agreed     
C. joy          
C. experience   
C. missing    
C. went      
C. really   
C. wanted   
D. wind        
D. reminded    
D. crossing    
D. land        
D. while       
D. quick       
D. afraid      
D. open        
D. serves      
D. crowded        
D. clearly     
D. man        
D. airplane    
D. insisted   
D. future      
D. practice   
D. enjoying   
D. rode        
D. suddenly   
D. decided    
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