问题 实验题

如图学习小组甲、乙所示进行乙醇的催化氧化实验,试管A中盛有无水乙醇,B中装有Cu或CuO(用石棉绒作载体),C中装的是蒸馏水。请回答下列问题:

甲                                 乙

⑴甲中B内放置的是       ; 乙中B内放置的是        

乙向试管A中鼓入空气的目的是_____________________。

⑵甲乙装置中A试管为什么都要水域加热:               

⑶甲中玻璃管中可观察到的现象是_____________________;

甲和乙中反应的化学方程式分别是_______________________;

                                              

⑷在实验过程中试管C导管口有气泡冒出,从液面逸出的气体的主要成分是_______________________。

答案

⑴CuO;Cu ;使空气通过乙醇,形成乙醇和空气的混合气体; ⑵使A中乙醇均匀受热挥发,蒸汽流稳定;

⑶黑色固体变红 CuO+C2H5OHCH3CHO+H2O+Cu ;

2C2H5OH+O2 2CH3CHO+2H2O    ⑷N2

由教材实验可以知道:乙醇被氧化成乙醛,在Cu做催化剂加热条件下被氧气氧化成乙醛,也可以被热的氧化铜氧化成乙醛。

甲中没有氧气,所以B中装的是CuO ;乙的A中通入空气的目的是提供氧化乙醇的氧化剂氧气并形成乙醇和空气的混合气体,当混合气体通过铜丝后,在热Cu催化下氧气将乙醇氧化成乙醛,乙中B装的是Cu;由于乙醛易溶解于水,所以最后出来的气体主要是氮气。

完形填空

对话填空(共10小题;每小题1分,满分10分)

(C=Clare;M="Mr" Brown)

C:Can I have a (76) w      with you now, Mr Brown?               小题1:           

M:Sure ,what is it?

C:Well.I fell very lonely .How I wish I had a friend to (77) t      to!   小题2:           

M:Sit here,please.Take it easy.

C:Well,I (78) s      most of my time studying and I hardly talk to      小题3:            

my classmates.

M:I see .Actually many middle school students have this problem.

C:Really? Then what should I do. 

M:The most (79) i      thing is to build confidence. You should believe 小题4:          

that you are a good person to (80) m      friends with.              小题5:           

C:I see .What else can I do? 

M:Smile at your classmates.Your smile will show that you are (81) f      小题6:         

to them so that they may love to be friends with you and talk to you.

C:Sometimes ,I do want to talk ,but I just don't know how to begin

a (82 )c                                                        小题7:      

M:There are many things you can talk about .You can (83) d      your  小题8:           

Studies and you can also talk about your hobbies with each other.If a

Classmate is in (84) t     , you should be ready to help.               小题9:            

C:Well, thanks , Mr Brown. I'm (85) f     much better now.           小题10:          

M:you'are welcome, 'm sure you will have many friends very soon.

单项选择题