问题 选择题

下列除杂质(括号内为杂质)的方法正确的是

A.苯(甲苯):加酸性KMnO4溶液,振荡后分液

B.甲烷(乙烯):通过盛有溴水的洗气瓶

C.乙醇(丙三醇):用分液漏斗分液

D.苯(苯酚):加浓溴水,后过滤

答案

答案:B

A错,苯、甲苯混合物中加加酸性KMnO4溶液,甲苯能被酸性KMnO4溶液氧化成苯甲酸,苯不能被氧化,但苯和苯甲酸能溶解在一起,不能分液;

B正确,乙烯能与溴水发生加成反应,而甲烷不能反应。

C错,乙醇与丙三醇是互溶的,不能用分液漏斗分液;

D错,苯酚与浓溴水会发生取代反应,生成三溴苯酚,但三溴苯酚能与苯互溶,不能过滤。

阅读理解

1. Know the fire exit (消防通道) and plan two ways out.

2.If you hear the smoke alarm or smell smoke, Shout "Fire! Everyone out!" to awaken anyone

still asleep and to let others know there is a fire.

3. Feel the door with the back of your hand if there's a fire.

●If it's hot, use the window if possible. A warm door may mean there is a fire outside.

●If the door is cool, open it slowly, then crawl out of the building.

●If heat and smoke come in when you open the door, close it tightly, and find another way out.

4. Don’t hide! Go outside! Never hide under beds when there is a fire.

5. Stay low and crawl below the smoke to safety.  Smoke goes up with the warm air and the air below is fresher.

6. Don't stop to put on your clothes or look for valuables (财物).

7. Don’t go back into a burning house for any reason.

8.Wait for your family at a meeting place outside,such as a big tree or the entrance( 入口) of the housing estate(小区), to know everyone is safe.

9. If you can’t escape from a room because of a fire outside, put wet clothing, towels, or blankets at the bottom of the door to keep the smoke out.  

10.Open your window and ask for help if you can’t escape through the door.

11. Stop, Drop and Roll if your hair or clothes are on fire. Shout for help, but don't run. Running makes fire burn faster.

Stop where you are.

Drop to the ground while covering your face with your hands to protect it.

Roll over and over until the fire is out.

小题1:Why do you shout "Fire! Everyone out!”?

A. To ask people to put on their clothes

B. To ask people to look for valuables.

C. To awaken anyone still asleep and to let others know there is a fire.

小题2:If the door is hot,______________

A. open it slowly, then crawl out of the building.

B. use the window if possible

C. open it and walk out of the buliding

小题3:From the passage, we know we should__________ if there is a fire.

A. plan two ways out

B. look for valuables first

C. hide under beds

小题4:If your hair or clothes are on fire,__________.

A. run quickly

B. stop, drop and roll

C. jump downstairs

小题5:The title of the passage is :________.

A. Stop, drop and roll

B. Fire safety rules

C. Fire is dangerous

单项选择题