问题 问答题

实验室制取氧气所需装置如图1所示.回答下列问题:

(1)写出仪器名称:a      ,b       

(2)用过氧化氢溶液和二氧化锰制取氧气时,所选用的发生装置是     (填序号),其反应的化学方程式是               ,所选用的收集装置是或       (填序号).

(3)若用锌与稀硫酸制取氢气,反应的化学方程式是             ,其收集装置不能选   (填序号).

(4)若采用如图2所示装置制取氧气并测定其体积,实验前应检查装置的气密性.为了准确测定氧气的体积,有人提出读数时应该注意以下事项:①容器中气体必须冷却至室温;②长颈漏斗不能倾斜;③必须使量气管和长颈漏斗两边液面相平;④视线应与液体凹液面最低处保持水平.你认为必须要做到的是            (填序号).

答案

(1)试管;集气瓶    (2)B;2H2O22H2O+O2↑;C或D

(3)Zn+H2SO4═ZnSO4+H2↑;D    (4)①③④

题目分析:(1)a是试管,b是集气瓶,故答案为:试管;集气瓶;

(2)用过氧化氢溶液和二氧化锰制取氧气时,属于固液在常温下制取气体,所选用的发生装置选B,其反应的化学方程式是2H2O22H2O+O2↑,氧气的密度比空气大,不易溶于水,可用向上排空气法或排水法收集;故答案为:B;2H2O22H2O+O2↑;C或D;

(3)锌与稀硫酸制取氢气,反应的化学方程式是Zn+H2SO4═ZnSO4+H2↑;氢气的密度比空气小,可用向下排空气法收集,氢气难溶于水,可用排水法收集,故答案为:Zn+H2SO4═ZnSO4+H2↑;D;

(4)①容器中气体必须冷却至室温,测量准确,故正确;

②与长颈漏斗倾斜与否无关,只要保持量气管和长颈漏斗两边液面相平,内外压强就相等,故错误;

③必须使量气管和长颈漏斗两边液面相平,使内外压强相等,故正确;

④视线应与液体凹液面最低处保持水平,故正确.

故选①③④.

点评:本题重点考查实验室制取气体的发生装置和收集装置、以及实验中的注意事项和化学方程式的书写等,需要同学们对常见实验做到了然于心.

阅读理解

Mr. Ma, a famous mental doctor from Beijing once said at an important meeting, “Now many young students can have problems with their minds. Some students become worried because they have to study very hard. Others have trouble getting on well with people around them like their parents and classmates. Parents and teachers should care more about this problem.”

Then Mr. Ma gave some examples. One patient, a middle school student from Xi’an, was doing  badly in his lessons. He thought his teachers and friends often laughed at him, and he became so nervous and worried that one night he left his home without telling his parents. Another student, a 14-year-old school girl form Shanghai, was very afraid of exams. While she was reading the exam paper, she couldn’t think of anything to write.

A recent report from Jiefang Daily says about 18% of young students in Shanghai have mental problems. They often feel worried and very unhappy. Unluckily many of them won’t go and ask for help. Some think they will look stupid if they go to see a doctor. Others won’t talk about their secrets.

At the end of the meeting, Mr. Ma offered some good ideas to young people:

●Talk to your parents ore teachers often.

●Take part in group activities.

●Try to get on well with the people around you.

●Go to see a doctor if you often feel unhappy.

小题1:The students who often become worried or have trouble getting on with others may have ______

A. no parents         B. poor memories            C. mental problems

小题2:The school girl’s problem happened whenever she ________

A. studied very hard    B. had exams               C. talked with her parents

小题3:Some of those with metal problems won’t ask for help because _____

A. they don’t’ want to tell their secrets to others 

B. their parents are too busy to look after them.

C. doctors can’t help them with the problem

小题4:The underlined word “stupid” in this passage means ______

A. studying         B. happy                C. not clever

小题5:According to the last part, which of the following is a good idea?

A. It’s important for children to live with their parents.

B. It’s useful for students to keep quiet in class.

C. It’s not necessary for young people to have more group activities.

单项选择题