问题 选择题

对于可逆反应:4NH3(g)+5O2(g)4NO(g)+6H2O(g),下列说法正确的是(  )

A.达到化学平衡时,4v(O2)=5v(NO)

B.若单位时间内生成xmol NO的同时消耗xmol NH3,则反应达到平衡状态

C.达到平衡状态时,若增加容器体积,则正反应速率减小,逆反应速率增大

D.化学反应速率关系是:2v(NH3)=3v(H2O)

答案

答案:A

根据反应速率之比等于化学方程式的计量数之比有:4v(O2)=5v(NO),所以4v(O2)=5v(NO)时表示化学反应达到平衡,故A项正确;生成NO、消耗NH3均为正反应的变化,未表示逆反应的变化情况,故B项错误;由于反应物、生成物均为气体,所以增加容器体积,正反应速率和逆反应速率都会减小,故C项错误;因为v(NH3)∶v(H2O)=2∶3,即3v(NH3)=2v(H2O),故D项错误。

阅读理解

阅读理解

       Henry works in a factory. He comes from a poor family and was in school for only four years. He

has to do the hard work, but he is paid less. He likes to watch football matches very much and spends

much time on them.

       One afternoon there was a big football match on the playground. He borrowed some money from

his friend and hurried there. There were a lot of people there. And all the tickets were sold out. He was

sorry for it. He saw a pole outside the playground and climbed it quickly. A policeman came and said,

"It is dangerous to stay on it! Come down!"

       " Wait a minute, please!" Henry said and just at that moment the policeman heard cheers on the

playground and asked in a hurry, " which team has kicked a goal?" " ours!" " wonderful! You can stay

there. But take care!"  The policeman said happily and left. When the match would be soon over, he

came back again and asked, " who has won?" " Theirs, 3:2 " " Come down," the policeman said angrily. " Such a match is not worth watching!"

       Henry had to come down. But soon they heard cheers again. The policeman said in a hurry, " Climb

up quickly and see who has kicked a goal."

1. From the passage we know that _________.

A. Henry doesn't like his work              

B. Henry comes from a rich family.

C. Henry doesn't like the policeman          

D. Henry is paid less.

2. Henry failed to get a ticket for the match that day because ___________.

A. he had no money to buy a ticket            

B. he didn't want to buy a ticket

C. he had no time to buy a ticket              

D. all the tickets were sold out

3. The policeman asked Henry to come down the pole at first because ____________.

A. it was dangerous                        

B. Henry had no ticket

C. their team kicked a goal                  

D. the other team kicked a goal

4. From the third paragraph, we can guess that _____________.

A. the policeman wanted to teach Henry a lesson.

B. the policeman tried to please Henry

C. the policeman didn't like Henry.

D. the policeman was also a football fan.

5. The policeman asked Henry to climb up the pole ____________

A. to cheer for their team                    

B. to see the result of the match

C. to cheer for the other team                 

D. to say goodbye to their team

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