问题 选择题

下列说法正确的是(  )

A.1mol葡萄糖能水解生成2molCH3CH2OH和2molCO2

B.在鸡蛋清溶液中分别加入饱和Na2SO4、CuSO4溶液,都会因盐析产生沉淀

C.油脂不是高分子化合物,1mol油脂完全水解生成1mol甘油和3mol高级脂肪酸

D.欲检验蔗糖水解产物是否具有还原性,可向水解后的溶液中直接加入新制的Cu(OH)2并加热

答案

A、葡萄糖为单糖,不能水解,在无氧呼吸条件下,1mol葡萄糖可以生成2molCH3CH2OH和2molCO2,故A错误;

B、鸡蛋清的主要成分为蛋白质,加入饱和硫酸钠溶液,可以使蛋白质因盐析产生沉淀,盐析是一个可逆的过程;加入饱和硫酸铜溶液会因变性产生沉淀,变性是不可逆的,故B错误;

C、油脂不是高分子化合物,在化学成分上都是高级脂肪酸跟甘油所生成的酯,1mol油脂完全水解生成1mol甘油和3mol高级脂肪酸,故C正确;

D、蔗糖水解后溶液呈酸性,应先用NaOH调节至碱性,再用银氨溶液或新制的氢氧化铜检验水解产物的还原性,否则实验容易失败,故D错误.

故选C.

完形填空
完形填空
     It's no secret that many children would be healthier and happier with adoptive parents than with the
parents that nature dealt them. That's especially__1__of children who remain in homes where they're
badly treated__2__the law blindly favors biological parents. It's also true of children who__3__for
years in foster (寄养) homes because of parents who can't or won't care for them but__4__to give up
custody (监护) rights.
     Fourteenyearold Kimberly Mays__5__neither description, but her recent court victory could
__6__help children who do. Kimberly has been the__7__of an angry custody battle between the
man who raised her and her biological parents, with whom she has never lived. A Florida judge__8__
that the teenager can remain with the only father she's ever known and that her biological parents have
"no legal__9__" on her.
     Shortly after__10__in December 1978, Kimberly Mays and another baby were mistakenly
switched and sent home with the__11__parents. Kimberly's biological parents, Ernest and Regina
Twigg, received a child who died of a heart disease in 1988. Medical tests__12__that the child wasn't
the Twiggs' own daughter, but Kimberly was, thus leading to a custody__13__with Robert Mays. In
1989, the two families__14__that Mr. Mays would maintain custody with the Twiggs getting__15__
rights. Those rights were ended when Mr. Mays decided that Kimberly was being__16__.
     The decision to__17__Kimberly with Mr. Mays caused heated discussion. But the judge made it
clear that Kimberly did have the right to sue (起诉)__18__her own behalf. Thus he made it clear that
she was__19__just a personal possession of her parents. Biological parentage does not mean an
absolute ownership that cancels(取消) all the__20__of children.

( )1. A. terrible    
( )2. A. but        
( )3. A. settle      
( )4. A. have        
( )5. A. likes      
( )6. A. actually    
( )7. A. victim      
( )8. A. ruled      
( )9. A. expectation
( )10. A. birth      
( )11. A. biological
( )12. A. examined  
( )13. A. battle    
( )14. A. thought    
( )15. A. equal      
( )16. A. harmed    
( )17. A. make      
( )18. A. by        
( )19. A. more than  
( )20. A. freedom    
B. sad            
B. if              
B. live            
B. refuse          
B. gives          
B. eventually      
B. object          
B. believed        
B. action          
B. judgment        
B. own            
B. explained      
B. right          
B. quarreled      
B. same            
B. forbidden      
B. leave          
B. through        
B. no more than    
B. happiness      
C. true            
C. when            
C. suffer          
C. stick          
C. fits            
C. successfully    
C. sacrifice      
C. ordered        
C. effect          
C. operation      
C. kind            
C. decided        
C. agreement      
C. agreed          
C. visiting        
C. wounded        
C. give            
C. on              
C. not more than  
C. rights          
D. natural    
D. because    
D. gather    
D. fail      
D. knows      
D. abruptly  
D. teenager  
D. indicated  
D. claim      
D. school    
D. wrong      
D. showed    
D. decision  
D. prepared  
D. speaking  
D. hidden    
D. keep      
D. in        
D. less than  
D. ideas      
单项选择题