问题 问答题

下图是实验室用于制取、干燥和收集气体的装置图.

(1)若用装置A制取氧气,装置中放入的药品为:______ 和______.

(2)若用装置B制取氧气,写出一个反应的化学方程式:______.

(3)若想用排水法收集干燥的氧气(C中盛满水),则装置端口连接顺序是

a______→______→______→______→______.

答案

(1)发生装置A用于固体与液体发生反应,因此选用该装置制取氧气时,装置内所加入的药品应为液体过氧化氢溶液和固体催化剂二氧化锰;

(2)发生装置B用于对固体加热制取气体的反应,因此选用该装置制取氧气时,应选用加热分解高锰酸钾或在二氧化锰催化下加热分解氯酸钾制取氧气,发生反应的化学方程式为2KClO3

MnO2
.
2KCl+3O2↑或2KMnO4
  △  
.
 
K2MnO4+MnO2+O2↑;

(3)从导管a排出的气体通入浓硫酸时,氧气应从伸入液面以下的b导管进入,这样可充分吸收气体中所含有的水;然后将从b管排出被干燥了的氧气通入装满水的装置C中,为排出瓶内的水,氧气应从伸入较短的e导管进入而使瓶内水由导管d排出,从而完成氧气的收集.

故答案为:

(1)过氧化氢(或H2O2),二氧化锰(或MnO2);

(2)2KClO3

MnO2
.
2KCl+3O2↑(或2KMnO4
  △  
.
 
K2MnO4+MnO2+O2↑);

(3)b,c,e,d.

完形填空
Dear friends,
Please come to my house for a welcome party for Lisa.
Lisa is from America. She moved here      her parents last week. She’s my new friend and neighbor. Her house is next to      . We usually go to school together.
Lisa and I were born in the same year. She is as old as I am.     she is much taller. Lisa is very beautiful. Her big eyes make her look     .  She’s very helpful, too. She      likes to help others. She also has a good sense of humor. She likes      funny jokes. I never feel      or unhappy when she’s with me. Lisa is a true friend. When     worries me.  I always go to her for help. I can tell her anything because she can keep secrets. We like to talk with each other because we always have the same     .
Lisa wants to make friends with all of you. She can tell us about her life in America in English. I believe you will be      with her, because she is a cheerful girl.
The party will begin at 7:00 p.m. in my house on Saturday. We look forward to seeing you then.
Yours,
Betty
小题1:
A.toB.by C.withD.for
小题2:
A.me B.mine C.us D.ours
小题3:
A.But B.However C.AndD.Because
小题4:
A.terrible B.sad C.old D.smart
小题5:
A.never B.always C.sometimes D.hardly ever
小题6:
A.saying B.speakingC.telling D.talking
小题7:
A.interested B.good C.excited D.bored
小题8:
A.something B.everything C.nothing D.anything
小题9:
A.lesson B.hobby C.telephone D.test
小题10:
A.happy B.strange C.shyD.unhappy
填空题