问题 填空题

(10分)可用于分离或提纯物质的方法有:①过滤 ②蒸馏 ③加热分液(填序号)

(1)除去石灰水中悬浮的CaCO3颗粒      

(2)除去NaCl晶体中混有的碘单质       

(3)分离石油中各不同沸点范围的成分      

(4)分离水和苯的混合物     

(5)分离CCl4(沸点76.75℃)和甲苯(沸点110.6℃)____________。

答案

  ① ; ⑵   ③ ; ⑶   ② ; ⑷   ④ ; ⑸   ②   

题目分析:萃取分液法用来分离在不同溶剂中的溶解度不同的物质,加热分解法用来分离加热易分解的物质,结晶法用来分离温度变化时溶解度变化相差较大的可溶物,分液法用来分离互不相溶的液体物质,蒸馏法用来分离沸点不同的物质,过滤法用来分离固液混合物。

(1)除去石灰水中悬浮的CaCO3颗粒,根据CaCO3的溶解性,是不溶于水的物质,要和石灰水分离,可以采用过滤的方法,所以本题答案为:①;

(2)除去氯化钠中混有的碘单质,根据碘的性质,是一种受热易升华的物质,而加热对氯化钠没有影响,所以本题的答案为:③;

(4)水和苯互不相溶,可用分液的方法分离,故答案为:④;

(5)四氯化碳与甲苯的沸点不同,可用蒸馏的方法分离,故答案为:②。

点评:本题考查物质的分离,题目难度不大,要明确各种分离的方法及其适用范围,做题时注意把握物质的性质和分离的原理。

单项选择题
阅读理解

Once many years ago, I pulled a family out of a burning car somewhere in Wyoming. Last week I received a telephone call from a woman who could not stop crying as she told me that one of my stories had saved her son from committing suicide. In closing she called me a hero.

That got me thinking about what a hero is. Was I a hero because I pulled a family from a burning car? If so, how could I be a hero just because I wrote a story that saved someone’s life?

Today I looked up the word “hero” in the dictionary to see exactly what it meant. It read “a person who does something brave” and also “a person who is good and noble”.

That statement impressed me more than the part about being brave. So I thought about something very important. And I remembered what happened to me years ago.

After my marriage of twenty years ended, I was in such a condition. I was within hours trying to get up enough courage to end the pain and misery. When I returned home, someone had sent me a card in the mail which told me how much they would appreciate me as a friend. That wonderful card probably saved my life. That person, without even knowing it, saved a life and became a hero.

The many stories I kept writing in the following years saved the life of a teenage boy. In turn that makes the person who sent me the card a double hero. I suppose that is why I fight so hard to help the children now living in orphanages (孤儿院). Most children come out of these institutions with a very hard and bitter attitude against the world. The gifts we send them let them know that they have not been forgotten. Hopefully, most of them will never hurt anyone because of the kindness shown to them by those of us who cared. If it works, we will also become "heroes".

小题1:The main idea of the passage is _______________.

A.why the writer should be a hero

B.whether the writer is a hero

C.what a hero exactly is

D.that everyone is a hero小题2:Why did the woman call the writer a hero at the end of the call?

A.Because he was cute and kind to everybody

B.Because he saved a family from a burning car.

C.Because he asked her son not to kill himself.

D.Because his story saved her son’s life.小题3:What does the underlined word “it” in the last sentence of Paragraph 5 refer to?

A.The wonderful card the writer received.

B.The action of sending the card.

C.The fact that the sender helped the writer.

D.The fact that the sender was a friend of the writer.小题4:According to the writer, who can be considered as a hero?

A.A person who helps someone in trouble.

B.A person who writes wonderful stories.

C.A person who can hold a door for others.

D.A person who is brave.