问题 问答题

在实验室里制取氧气的研究中,有下列仪器可供选用(铁架台、导管、橡皮塞等已省略)

(1)写出下列编号仪器的名称:①______; ②______; ③______.

(2)在实验室里制取氧气,你选用的药品是______,其反应的化学方程式为______.

(3)根据你选用的药品,设计一套制取氧气的发生装置,你选择的仪器是(填编号)______.

(4)检查你所设计的装置气密性的方法是______.

(5)从事科学实验的重要环节是进行科学实验的设计.科学实验的正确步骤应为:①明确实验目的②收集有关资料③设计合理方案④进行科学实验.请你按照以上四步,完成以下实验设计,根据装置图回答下列问题:(所用装置图用序号表示)

双氧水(H2O2)是一种无色液体,在二氧化锰的催化作用下能迅速分解出氧气,实验室常用这种方法制取氧气.

①明确实验目的:在实验室里制取氧气

②收集有关资料:双氧水是一种无色______,二氧化锰是一种______(填颜色);反应条件______;氧气的密度______于空气的密度且______水.双氧水与二氧化锰混合制取氧气的化学方程式为______.

③设计合理方案:发生装置选用______,收集装置选用______.

④进行科学实验.

答案

(1)①长颈漏斗;②酒精灯;③试管;

(2)在实验室里制取氧气,可以选用的药品是:氯酸钾和二氧化锰的混合物;反应的方程式为:2KClO3

MnO2
.
2KCl+3O2↑;

(3)用加热氯酸钾和二氧化锰的混合物的方法制取氧气的发生装置,你选择的仪器是试管和酒精灯;

(4)检查该简易装置气密性的方法是:把导管的一端浸在水里,两手紧贴容器的外壁;如果装置不漏气,里面的空气受热膨胀,导管口有气泡冒出;

(5)双氧水是一种无色液体,二氧化锰是一种黑色固体,反应条件是常温,氧气的密度大于空气的密度且不易溶于水,双氧水与二氧化锰混合制取氧气的化学方程式为:2H2O2

 MnO2 
.
 
2H2O+O2;该法制取氧气发生装置的特点属于固液常温型的A装置,因为氧气不易溶于水,密度比空气大,故采用的收集方法为:排水法或向上排空气法.

故答案为:(1)①长颈漏斗;②酒精灯;③试管;

(2)加热氯酸钾和二氧化锰的混合物  2KClO3

MnO2
.
2KCl+3O2↑;

(3)②③;

(4)把导管的一端浸在水里,两手紧贴容器的外壁;如果装置不漏气,里面的空气受热膨胀,导管口有气泡冒出;

(5)②液体;黑色固体;常温;大;不易溶于;2H2O2

 MnO2 
.
 
2H2O+O2; ③A;E或D

阅读理解

阅读理解

     From the beginning of human history, wild animals provided food, clothing and sometimes medicine

for man. We may not depend as much on wild animals now. But we hear about them every day.

Americans use the names of animals in many ways. Automobile manufacturers and gasoline companies

especially like to use big cats to sell their products. They like lions, tigers and wildcats. When Americans

say wildcat, they usually mean a_lynx, an_ocelot_or_a_bobcat. All these cats attack quickly and fiercely.

So wildcats represent something fast and fierce.  

     An early American use of the word wildcat was quite different. It was used to describe members of

Congress who declared war on Britain in 1812. A magazine of that year said the wildcat congressmen

went home. It said they were unable to face the responsibility of having involved their country in an

unnecessary war.

     Wildcat also has been used as a name for money in the 1800s. At that time, some states permitted

banks to make their own money. One bank in the state of Michigan offered paper money with a picture

of a wildcat on it. Some banks, however, did not have enough gold to support all the paper money they

offered. So the money had little or no value. It was called a wildcat bill or a wildcat banknote. The

banks who offered this money were called wildcat banks. A newspaper of the time said those were the

days of wildcat money. It said a man might be rich in the morning and poor by night.

     Wildcat then was also used for an oil well or gold mine that had almost no oil or gold in it. Dishonest

developers would buy such property. Then they would sell it and leave town with the money. The

buyers were left with worthless holes in the ground.Today, wildcat oil wells are in areas that are not

known to have oil.

1. What is the main idea of the passage?

A. Wildcats and their stories.

B. Wildcats and their characters.

C. Varieties of animal species.

D. Relationship between animals and humans.

2. From the passage we can know that__________.

A. wildcats represent the state of Michigan

B. the use of wildcats was not always the same

C. wildcats are the best friend of human beings

D. honest developers never buy wildcat oil wells

3. The underlined words "a lynx, an ocelot or a bobcat" in Paragraph 1 may refer to "__________".

A. gasoline companies

B. automobile manufacturers

C. names of wildcats

D. brands of automobile

4. Which of the following would people like to have or trust according to the passage?

A. Wildcat congressmen.  

B. Wildcat oil wells.

C. Wildcat banks.  

D. Wildcat cars.

5. It can be inferred that during the days of wildcat money__________.

A. people couldn't buy anything with the money

B. people didn't know how to save money

C. the rich invested too much on oil wells

D. people complained and suffered a lot

单项选择题