问题 选择题

已知氯化铝的熔点为190℃(2.02×105Pa),但它在180℃即开始升华。在500K和1.01×105Pa时,它的蒸气密度(换算为标准状况)为11.92g/L。有关氯化铝的叙述中错误的是

A.氯化铝是共价化合物

B.氯化铝的化学式应为Al2Cl6

C.氯化铝的结构式为:,分子结构中有配位键

D.在一定条件下,将AlCl3晶体加热至融化,熔融态的AlCl3可以导电

答案

答案:D

题目分析:D项:AlCl3是共价化合物,熔融态的AlCl3不能导电,故错。故选D。

点评:本题考查的是氯化铝的相关知识,题目难度适中,需要注意的是氯化铝是共价化合物,这一点比较特殊。

阅读理解

阅读理解。

     If you go to a fast food restaurant, you will probably see a lot of teenagers. Today many teenagers

are overweight, and some of this is because of their bad eating habits. Most teenagers love food with a

lot of fat, oil, salt and sugar. People often call this kind of food "junk food" (垃圾食品)

      But bad eating habits go beyond fast food. We find many teenagers eating unhealthily. Some don't

have breakfast before they go to school. During the day, some don't have right meal for lunch. In a

survey at one school, scientists found that many students didn't follow a healthy diet. They didn't like

vegetables, and they didn't like to eat fruits. They preferred (更喜欢) to eat food with a lot of salt,

sugar or fat.

     Parents today also worry about their children's diet. Some doctors give the following advice:

★ Teenagers shouldn't eat too much junk food.

★ Teenagers shouldn't eat food with too much salt. Salt can cause high blood pressure (高血压) in the

     future.

★ Teenagers should eat food with less fat, oil and sugar.

★ Teenagers need to eat some fruits and vegetables every day. Fruits and vegetables are rich in vitamins

     and have little fat.

★ Teenagers need to drink more milk. Milk will help their bones grow.

★ Teenagers need to eat breakfast every day. This is good for their body and mind.

1. "Junk food" includes a lot of _____.

[ ]

A. milk and sugar

B. fruits and sugar

C. vegetables and salt

D. fat, oil, salt and sugar

2. In a recent survey at one school, scientists found that many students liked _____. [ ]

A. vegetables

B. unhealthy food

C. fruits

D. healthy food

3. What does the word "beyond" mean in Chinese in this passage?

[ ]

A. 超出

B. 不如

C. 相等

D. 在后面

4. In this passage, doctors think that teenagers should eat more _____.[ ]

A. food with no vitamins

B. fat and sugar

C. vegetables and fruits

D. salt and oil

5. The best title for this passage is _____. [ ]

A. Bad manners

B. Junk food

C. Unhealthy food

D. Advice on healthy

选择题