问题 填空题

实验室欲用NaNO3固体配制80 mL 1.4 mol·L-1的NaNO3溶液,试回答:

(1)用不到的仪器是__________;

A.烧杯           B.500 mL容量瓶         C.量筒               

D.胶头滴管        E.玻璃棒                 F.100 mL容量瓶

(2)配制时应称取NaNO3__________g;

(3)实验开始时,需检查容量瓶__________;

(4)在配制一定物质的量浓度溶液的实验中,下列操作对所配溶液浓度无影响的是(写字母) __________;会使所配溶液浓度偏大的是__________;会使所配溶液浓度偏小的是__________。

A.在烧杯中溶解溶质,搅拌时不慎溅出少量溶液

B.未将洗涤烧杯内壁的溶液转移入容量瓶

C.容量瓶中所配的溶液液面未到刻度线便停止加水

D.将配得的溶液从容量瓶转移到干燥、洁净的试剂瓶中时,有少量溅出

E.将烧杯中溶液转移到容量瓶之前,容量瓶中有少量蒸馏水

F.容量瓶中液面将达到刻度线时,俯视刻度线和液面

答案

(1) B    (2) 11.9   (3) 是否漏水   (4) D、E   C、F    A、B

题目分析:(1)由于没有80ml的容量瓶,所以应该配制100ml,则不需要的仪器是500ml容量瓶,答案选B。

(2)配制时应称取硝酸钠固体的质量是0.1L×1.4mol/L×85g/mol=11.9g。

(3)实验开始时,需检查容量瓶是否漏水。

(4)根据可知,在烧杯中溶解溶质,搅拌时不慎溅出少量溶液,则溶质的质量减少,浓度偏低;未将洗涤烧杯内壁的溶液转移入容量瓶,同样是溶质质量减少,浓度偏低;容量瓶中所配的溶液液面未到刻度线便停止加水,则容量瓶中溶液体积减少,浓度偏高;将配得的溶液从容量瓶转移到干燥、洁净的试剂瓶中时,有少量溅出,浓度不变;将烧杯中溶液转移到容量瓶之前,容量瓶中有少量蒸馏水,不会影响实验结果;容量瓶中液面将达到刻度线时,俯视刻度线和液面,则容量瓶中溶液体积减少,浓度偏高。

点评:该题是高考中的常见题型,属于中等难度试题的考查,试题基础性强,侧重对学生基础知识的巩固和训练,主要是考查学生灵活运用基础知识解决实际问题的能力,有利于培养学生的实验设计能力。该类试题主要是以常见仪器的选用、实验基本操作为中心,通过是什么、为什么和怎样做重点考查实验基本操作的规范性和准确性及灵活运用知识解决实际问题的能力。该题的难点是误差分析,根据cBnB/V可得,一定物质的量浓度溶液配制的误差都是由溶质的物质的量B和溶液的体积V引起的。误差分析时,关键要看配制过程中引起V怎样的变化。在配制一定物质的量浓度溶液时,若nB比理论值小,或V比理论值大时,都会使所配溶液浓度偏小;若nB比理论值大,或V比理论值小时,都会使所配溶液浓度偏大,据此判断。

完形填空
完形填空。
     Scientists find that hard-working people live longer than average men and women. Career women are   1  
  than housewives, Evidence shows that   2   are in poorer health than the job-holders. A study shows   3    the
unemployment rate increases by 1%, the death rate increases correspondingly (相应地) by 2%. All this   4   one
point: Work is helpful to health.
     Why is work good for health? It is because work keeps people busy,   5   loneliness and solitude. Researches
show that people feel   6   and lonely when they have nothing to do. Instead, the happiest are those who are
  7  . Many high achievers who love their careers feel that they are happiest when they are working hard. Work
serves as   8    between man and reality. By work, people   9   each other. By collective activity, they find
friendship and warmth. This is helpful to health. The loss of work  10  the loss of everything. It affects man
spiritually and makes him liable to (易于)  11 
      12  , work gives one a sense of fulfillment and a sense of  13  . Work makes one feel his value and status in
society. When  14  finishes his writing or a doctor successfully  15   a patient or a teacher sees his students
   16  , they are happy  17 .
     From the above we can come to the conclusion  18    the more you work,  19   you will be. Let us work
hard,  20   and live a happy and healthy life.
( )1 A. more healthier        
( )2 A. career women          
( )3 A. that whenever          
( )4 A. comes down  to         
( )5 A. 不填                    
( )6 A. happy,
               interested      
( )7 A. busy                  
( )8 A. a river                
( )9 A. come 
               across           
( )10 A. means                
( )11 A. success             
( )12 A. Besides              
( )13 A. disappointment        
( )14 A. a worker              
( )15 A. manages              
( )16 A. raise                
( )17 A. in a word            
( )18 A. that                 
( )19 A. the lonelier
                 and weaker
( )20 A. study well           
B. healthier           
B. the busy            
B. whether             
B. equals to            
B. off                  
B. glad,
    joyful         
B. free                 
B. a gap               
B. come into
    contact with
B. stands              
B. death                
B. Nevertheless         
B. achievement         
B. a farmer             
B. controls            
B. grow                 
B. without a word       
B. which               
B. lonelier and
     weaker  
B. studying well        

C. weaker                  
C. the jobless             
C. that though              
C. adds up to              
C. in touch with            
C. cheerful,
     concerned    
C. lazy                     
C. a channel                
C. look down
    upon         
C. equals                  
C. victory                  
C. However                  
C. regret                  
C. a writer                
C. operates on              
C. rise                    
C. at a word                
C. what                    
C. happier and
     healthier    
C. study good           

D. worse                       
D. the hard-working             
D. since                       
D. amounts to                  
D. away from                   
D. unhappy,
    worried            
D. empty                       
D. a bridge                     
D. watch
     over                  
D. matches                     
D. disease                     
D. Yet                         
D. apology                     
D. a manager                   
D. deals with                  
D. increase                    
D. beyond words                
D. 不填.                       
D. the happier
     and healthier   
D. studying good               
单项选择题