问题 选择题

下列有关实验原理或实验操作正确的是

A.用蒸馏水湿润的pH试纸测量某溶液的pH=10

B.用10 mL量筒量取0.50 mol·L-1H2SO4溶液5.50 mL

C.向铁钉上镀铜时,铁钉连接直流电源的正极

D.盛装Na2CO3溶液的试剂瓶要使用胶塞

答案

答案:D

题目分析:A.pH试纸测量某溶液的pH时不能湿润。错误。B.10 mL量筒量取溶液的体积时只能估读到小数点后一位。错误。C.向铁钉上镀铜时,镀件铁钉连接直流电源的负极,镀层金属连接在电源的正极上。错误。D.Na2CO3溶液由于水解显碱性,容易与玻璃中的SiO2发生反应产生有粘性的Na2SiO3。若用玻璃塞就会导致玻璃瓶一玻璃塞粘在一起。所以盛装Na2CO3溶液的试剂瓶要使用胶塞。正确。

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Ladies and gentlemen,
       Attention, please! This is the service center (服务中心) of Wal Mart. Now Mrs Smith   1   a girl, Betty
Smith. She is   2  . She   3   short, brown hair and she is 1.25 meters   4  . She   5   a pink blouse and blue jeans.
If anyone sees her, please   6   our service center and   7   is 7669103, Betty Green, if you hear our message,
please come to   8  . On   9   floor as soon as possible (尽快). Mom   10   you. Thank you!
(     ) 1. A. looks for   
( ) 2. A. eight years old
(     ) 3. A. has       
( ) 4. A. tall       
(     ) 5. A. is putting on
(     ) 6. A. call       
( ) 7. A. the ID number
( ) 8. A. 205 Room
( ) 9. A. fifth        
( ) 10. A. is waiting            
B. is looking for      
B. eight year old      
B. have              
B. long              
B. wear              
B. to call            
B. the telephone number  
B. Room 205           
B. the fourth         
B. is waiting for    
C. is looking at     
C. eight-years-old 
C. wears         
C. high           
C. puts on         
C. calling       
C. the bus number      
C. 205 room        
C. the two        
C. wait for      
D. looks at            
D. eight-year-old    
D. with                
D. big                 
D. is wearing          
D. calls               
D. the message number  
D. 205 rooms           
D. three               
D. waits for         
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