问题 问答题

储氢纳米碳管研究成功体现了科技的进步.但用电弧法合成的碳纳米管常伴有大量的杂质--碳纳米颗粒.这种碳纳米颗粒可用氧化气化法提纯.其反应式为:3C+3K2Cr2O7+8H2SO4=3CO2+2K2SO4+2Cr2(SO43+8H2O

①此反应的氧化剂是______,氧化产物是______;

②H2SO4在上述反应中表现出来的性质是______(填选项序号)

A.酸性       B.氧化性     C.吸水性    D.脱水性

③由此可知上述反应所用硫酸应为______(填“浓”或“稀”)硫酸.

④请写出碳单质与硫酸反应时的化学方程式:______.

答案

①因反应中Cr元素的化合价降低,则K2Cr2O7为氧化剂,C元素化合价升高,C为还原剂,所以CO2为氧化产物,故答案为:K2Cr2O7;CO2

②该反应中,硫酸中各元素的化合价不变,反应生成硫酸盐,体现硫酸的酸性,故答案为:A;  

③因浓硫酸具有强氧化性,上述反应中硫酸作酸,则应为稀硫酸,故答案为:稀;  

④碳与浓硫酸反应生成二氧化碳、二氧化硫和水,该反应为C+2H2SO4(浓)

.
CO2↑+2SO2↑+2H2O,故答案为:C+2H2SO4(浓)
.
CO2↑+2SO2↑+2H2O.

单项选择题 B型题
完形填空
完形填空。
     Jerry is the kind of man you love to hate.He is always in a(n)__1__mood and always has
something__2__to say.In his opinion, the bottom line is your choice__3__you live a life.
     One morning, he did something you are never__4__to do in the restaurant business: he left
the back door open and was__5__up at gunpoint by three armed robbers.While trying to open
the__6__, with his hand shaking from__7__, he input the wrong code.The robbers beat him
and even__8__him.Luckily, Jerry was found__9__quickly after the robbers had fled and he
was rushed to the local first aid center.After 18 hours of operation and weeks of good care,
he was out of hospital with fragments (碎片) of the bullets still in his body.
     Jerry told me what happened after he was sent to hospital.He said the doctors were__10__.
They kept telling him he was going to be fine and__11__him into the emergency room.But when
he saw the__12__on the faces of the doctors and nurses, he got really__13__.In their eyes, he
__14__, "He's dying." He knew he needed to take__15__.There was a big,burly nurse shouting
questions at him.She asked if he was allergic (过敏的) to anything, and the doctors and nurses
stopped working as they waited for his reply.Jerry__16__for a while and then he decided to live.
He took a deep breath and said, "Yes.__17__!" Over their laughter, Jerry told them to operate
on him__18__he wouldn't die.
     Jerry lived, thanks to the skill of his doctors, but also because of his amazing__19__.I learnt
from him that every day we have the choice to live fully.
    Attitude, __20__, is everything.
( )1.A.exciting    
( )2.A.positive      
( )3.A.how          
( )4.A.advised      
( )5.A.pulled        
( )6.A.box          
( )7.A.nervousness  
( )8.A.knocked      
( )9.A.probably      
( )10.A.excited      
( )11.A.rolled      
( )12.A.surprise    
( )13.A.scared      
( )14.A.knew        
( )15.A.notice      
( )16.A.thought      
( )17.A.Medicine    
( )18.A.unless      
( )19.A.reply        
( )20.A.to be honest
B.good      
B.funny      
B.where      
B.imagined    
B.put        
B.safe        
B.worry      
B.killed      
B.relatively  
B.organized  
B.carried    
B.expressions
B.embarrassed
B.found      
B.order      
B.wondered    
B.Operation  
B.even if    
B.attitude    
B.in that case
C.usual      
C.new          
C.whether      
C.asked        
C.held          
C.counter      
C.unwillingness
C.knifed        
C.merely        
C.hard-working  
C.wheeled      
C.feeling      
C.disappointed  
C.meant        
C.breath        
C.judged        
C.Bullets      
C.as if        
C.opinion      
C.after all    
D.balanced          
D.different          
D.why                
D.supposed          
D.done              
D.door              
D.pressure          
D.shot              
D.reasonably        
D.great              
D.forced            
D.puzzles            
D.annoyed            
D.read              
D.action            
D.stopped            
D.Fragments          
D.before            
D.determination      
D.strictly speaking