精英家教网 > 高中地理 > 题目详情

【题目】下列除去杂质的方法正确的是( )

①除去乙烷中少量的乙烯:光照条件下通入Cl2,气液分离

②除去乙酸乙酯中少量的乙酸:用饱和碳酸钠溶液洗涤,分液、干燥、蒸馏

③除去CO2中少量的SO2:气体通过盛有饱和碳酸钠溶液的洗气瓶

④除去乙醇中少量的乙酸:加足量生石灰,蒸馏

A.①② B.②④

C.③④ D.②③

【答案】B

【解析】本题主要考查化学实验中物质的分离与除杂的方法。①中乙烷中有乙烯,在光照条件下通入氯气,乙烷与氯气发生取代反应;②中除去乙酸乙酯中少量的乙酸,加入饱和碳酸钠溶液洗涤后,乙酸与碳酸钠反应生成乙酸钠进入水层,然后经分液、干燥、蒸馏可以得到纯净的乙酸乙酯;③中除去二氧化碳中少量的二氧化硫,通过盛有饱和碳酸钠溶液的洗气瓶时,虽除去了二氧化硫,但是二氧化碳与碳酸钠溶液也发生反应,应选用饱和碳酸氢钠溶液;④中除去乙醇中少量的乙酸,加入足量的生石灰使乙酸变成沸点较高的乙酸钙,然后蒸馏可得到纯净的乙醇。所以②和④正确。故正确答案为B。

练习册系列答案
相关习题

科目:高中地理 来源: 题型:

【题目】B

The cost of keeping tigers alive in the wild is about $80 one square meter per year, say conservationists(自然资源保护论者) but only about $50m per year is being guaranteed. The figures come from a new assessment(评估) that suggests targeting efforts in 42 selected breeding sites.

About 3,500 tigers remain in the wild, and only about 1,000 breeding females. Although conservation programmes are operating in some countries, notably India, the tiger has actually disappeared from vast areas of Asia where it used to live.

Once found from Turkey to the eastern coast of Russia, it is now concentrated in small areas of South and East Asia, though even here it is extinct in some countries such as Pakistan and down to fewer than 50 individuals in others, including Cambodia, China, Laos and Vietnam.

The animals are found in only about 7% of their historical range. But the new study suggests conservation would benefit from concentrating efforts into still smaller areas specifically, into 42 source sites that make up only about 6% of the tigers current range, or about 0.5% of the area it used to span.

The immediate priority, however, must be to ensure that the few breeding populations still in existence can be protected and monitored. The figure of $80m per year is the cost of safeguarding and monitoring populations in these key sites. More than half of the figure is already being provided by the range states themselves, by international donors and by conservation groups.

The big hope this year is the Tiger Summit, to be hosted by Russias Prime Minister Vladimir Putin in St Petersburg. Originally planned for this week, it has been postponed until November in the hope of attracting a greater number of national leaders.

【1】Tigers have disappeared in ___________.

A. India B. Cambodia C. China D. Pakistan

【2】 Whats the primary task of conservationists according to this passage?

A. Enlarging the areas of tigers

B. Assessing the situation of tigers further

C. Providing more money for tiger protection

D. Protecting and monitoring the breeding female tigers

【3】How much is lacking to protect one tiger in the wild one square meter per year?

A. About $80. B. About $50.

C. About $30. D. About $20.

【4】 What can we know from the last paragraph?

A. Russia does best in tiger protection in the world.

B. Plans for tiger protection are difficult to carry out.

C. Some national leaders pay less attention to tiger protection.

D. More money is sure to be provided by Asian countries to protect tigers.

【5】 Which of the following is TRUE according to the passage?

A. There are about 3,500 tigers in the world.

B. Tigers mainly appear in South and East Asia nowadays.

C. The tigers current range decreased by 99.5% than it used to be.

D. More than half of the money used to protect tigers comes from the governments at present.

查看答案和解析>>

科目:高中地理 来源: 题型:

【题目】A

New scheme for getting children to and from school is being started by the education authorities in part of Eastern England. This could end the worries of many parents fearful for their children’s safety on the roads.

Until now the County Council has prepared to provide bus services for children living more than three miles from their school,or sometimes less if special reasons existed. Now it has decided that if a group of parents ask for help in organizing transport it will prepare to go ahead,provided the arrangement will not lose money and that children taking part will be attending their nearest school.

The new scheme is to be tried out this term for children living in Milton who attend Impington School. The children live just within the three mile limit and the Council has said in the past it will not undertake to provide free transport to the school. But now they have agreed to organize a bus service from Milton to Impington and back,a plan which has the support of the school’s headmaster.

Between 50 and 60 parents have said they would like their children to take part. Final calculations have still to be carried out,but a Council official has said the cost to parents should be less than £6.50 a term.

They have been able to arrange the service at a low cost because there is already an agreement with the bus company for a bus to take children who live further away to Impington. The same bus would now just make a extra journey to pick up the Milton children.

The official said they would get in touch with other groups of parents who in the past had asked if transport could be provided for their children,to see if they would like to take part in the new scheme.

【1】 The children the Council runs buses for now are those________.

A.whose parents are worried about them

B.who would have had to walk otherwise

C.who could not walk

D.who have to travel more than 3 miles

【2】Taking part in the Council’s trial scheme are children who________.

A.live in Milton and go to Impington School

B.live in Impington and go to Milton School

C.live in Milton and go to Milton School

D.live in Impington and go to Impington School

【3】The new bus service will run________.

A.on morning journey to school only

B.in connection with an existing service

C.only for children living more than three miles away

D.only in wet weather

【4】 Agreement to pay for the new bus service has been obtained from________.

A.the school’s headmaster

B.the County Council

C.the bus company

D.the parents

查看答案和解析>>

科目:高中地理 来源: 题型:

【题目】 用which,why,where或when改写以下句子。

1. The school year starts on the first of September.

The first of September is the day _________________________________________.

2. My brother stopped smoking because it is bad for his health.

The reason _________________________________________.

3. We went to Shanghai on our school trip.

The city _________________________________________.

4. I most like the late night show on TV.

The TV program _________________________________________.

5. My father works in a factory that makes telephones.

The factory _________________________________________.

6. She did her homework in this room.

This is the room _________________________________________.

7. I told you about the town on the phone.

This is the town ____________________________________.

8. Why is Tin Tin popular among children of different countries?

Do you know the reason __________________________________________?

9. Maybe one day we don’t have to go to school but just study at home.

The day may soon come _________________________________________.

10. I grew up in the small village and I’ll go back there after graduation.

After graduation, I will go back to the small village ___________________________________.

查看答案和解析>>

科目:高中地理 来源: 题型:

【题目】书面表达(满分20分)

假如你是李明上周你们学校请地震专家王教授来做了一次关于地震自救知识的讲座。请你就以下要点写一篇英语作文介绍这次讲座。

内容要点:

1. 介绍学习地震防护知识的重要性。

2. 演示如何在地震中保护自己。

3. 自己的感想……

注意:词数100左右。

参考词汇:预防措施precautionary measures

____________________________________________________________________________________________

____________________________________________________________________________________________

____________________________________________________________________________________________

____________________________________________________________________________________________

____________________________________________________________________________________________

____________________________________________________________________________________________

查看答案和解析>>

科目:高中地理 来源: 题型:

【题目】完成句子

1. I lived in _____________________and I used to write about the Olympic Games a long time ago.

我生活在你们所说的古希腊,并且我曾写过很久以前的奥运会的情况。

2. ____________________ theyre called the Winter Olympics.

那就是它们被叫作冬季奥运会的原因。

3. No other countries could join in, ______________________ slaves or women!

其他国家不能参加,奴隶和妇女也不可以!

4. ________ in the Summer Olympics ________ you have the running races,together with swimming,sailing and all the team sports.

跑步、游泳、帆船和所有团队项目都是在夏季奥运会上进行。

5. Theres __________________ competition among countries to host the Olympics ________ to win Olympic medals.

国与国之间争取奥运会承办权的竞争就跟争夺奥运奖牌一样激烈。

6. I had to sit down and rest __________________________.

我每4分钟就得坐下休息。

7. So just how do you __________________________?

那么,你该如何从竞争者中脱颖而出呢?

8. He will __________________________across the Atlantic.

他将参加一次重大的横渡大西洋的比赛。

9. You can swap out one system and ______________________.

您可以交换一个系统并且用其他的系统替换它。

10. But I also ______________________ he would probably not find my answer very helpful.

不过我也承认,他很可能觉得我的答案并没有什么帮助。

查看答案和解析>>

科目:高中地理 来源: 题型:

【题目】用价层电子对互斥模型推测下列分子或离子的立体构型。

(1)H2Se ;(2)NH2- ;

(3)BBr3 ;(4)CHCl3 ;

(5)SiF4

查看答案和解析>>

科目:高中地理 来源: 题型:

【题目】单词拼写

结合语境,根据汉语提示用单词的适当形式填空。

1. Mary explained what we were to do ________ (简要地).

2. We are all impressed by her total ________ (投入) to her job.

3. He was hurt falling off his bike, and now his shoulders are still ________ (疼痛的).

4. Lets go to the theatre first and eat at a restaurant ________ (后来).

5. We must ________ (分类) out the good apples from the bad ones.

6. Thanks for the ________ (邀请) to your birthday party.

7. To write such a book, one needs experience in ________ (除了) to time.

8. The children like to ________ (蘸) their bread into the milk.

9. To succeed, first of all, you should be ________ (有信心的) about yourself.

10. We didnt have a receiver ________ (灵敏的) enough to pick up the signal.

查看答案和解析>>

科目:高中地理 来源: 题型:

【题目】What time is it now?

A. 7:50. B. 8:00. C. 8:10.

查看答案和解析>>

同步练习册答案