问题 填空题

海水中含有丰富的人体不可缺少的碘元素,它以碘离子的形式存在.某学生为探究海带中碘元素的存在,按如下流程进行了实验:

回答下列问题:

(1)A步骤的操作名称是______;

A步骤用到的主要玻璃仪器是______(选填下列字母代号)

a.漏斗          b.分液漏斗       c.量筒        d.蒸发皿

(2)B步骤中加入的试剂是______.

(3)已经溶液1的阳离子是K+,则通入Cl2时反应的化学方程式为______,其中氧化剂是______.

答案

(1)依据提取流程分析海带灰悬浊液可以用过滤的方法得到溶液,除去不溶性杂质;用到的玻璃仪器有漏斗、烧杯、玻璃棒;故答案为:过滤,a;

(2)依据转化关系可知溶液1通入氯气把碘离子氧化为碘单质,加入B变蓝证明加入的是淀粉;故答案为:淀粉溶液;

(3)溶液1的阳离子是K+,依据分析可知,溶液中含有碘离子;通入氯气会和碘离子发生氧化还原反应;反应的离子方程式为:Cl2+2KI=2KCl+I2 ;氧化剂是化合价降低的氯元素,所以氧化剂是Cl2,故答案为:Cl2+2KI=2KCl+I2 ;Cl2

单项选择题
完形填空
完型填空。
    In the early 1800's, a boy named John lived in an orphanage (孤儿院) with several other children. Every
day was   1   working and Christmas was the one day of the year   2   the children did not work and received
a gift-an orange. The children   3   it so much that they kept it for weeks, and even   4  -smelling it,   5   it and
loving it. Usually they tried to preserve (保护) it for so   6   that it often went bad before they ate it.
    This year John knew he would soon be   7   enough to leave. He would save the orange until his birthday in
July. If he preserved it   8  , he might be able to eat it on his birthday.
    Christmas day finally came. The children were so   9   as they entered the dining hall. In his excitement,
John knocked over something, causing a big  10 . Immediately the master shouted, "John, leave the hall and
there will be no orange for you." John's heart  11 . He turned and ran back to the  12  room so that the children
wouldn't see his tears.
    Then he heard the door open and the children entered. Little Elizabeth with a  13  on her face held out her
small hands. "Here John," she said, "this is for you." As John  14  his head, he saw a big juicy  15  all peeled
and quartered … Each child had sacrificed (舍弃) their own orange by  16  a quarter and had created a big,
beautiful orange for him.
    John never forgot the sharing, love and personal  17  his friends had shown him that Christmas day.  18  
that day, after he became rich, every year he  19  send oranges all over the world to children everywhere. His
 20  was that no child would ever spend Christmas without a special Christmas fruit!
( )1. A. forced      
( )2. A. as          
( )3. A. needed      
( )4. A. months      
( )5. A. tasting    
( )6. A. much        
( )7. A. old        
( )8. A. seriously  
( )9. A. nervous    
( )10. A. cry          
( )11. A. jumped      
( )12. A. cold        
( )13. A. look        
( )14. A. shook        
( )15. A. gift        
( )16. A. sharing      
( )17. A. feelings    
( )18. A. In return for 
( )19. A. must        
( )20. A. desire      
B. passed        
B. when          
B. wanted        
B. days          
B. watching      
B. soon          
B. strong        
B. carefully    
B. excited      
B. disappointment   
B. stopped      
B. small        
B. tears        
B. lifted        
B. surprise      
B. breaking      
B. affairs      
B. In case of    
B. would        
B. idea         
C. taken      
C. while      
C. valued      
C. years      
C. pressing    
C. long        
C. tall        
C. secretly    
C. pleasant    
C. surprise    
C. broke      
C. old        
C. comfort    
C. put        
C. orange      
C. eating      
C. relation    
C. In memory of  
C. might      
C. meaning    
D. spent         
D. which         
D. liked         
D. seasons       
D. touching      
D. far           
D. experienced                     
D. softly        
D. eager         
D. noise         
D. settled       
D. lonely        
D. smile         
D. turned        
D. wonder        
D. taking        
D. sacrifice     
D. In search of  
D. should        
D. thinking