问题 选择题

(2011年四川南充,3题)化学实验操作的正确性、规范性是实验成功的关键,同时也反映了实验者的化学素养。下列实验操作中明显不正确的是( )

答案

答案:B

考点:

专题:实验操作型.

分析:A、给液体加热时,注意先预热、试管内液体的量,试管的倾斜度等;

B、稀释浓硫酸时,沿烧杯内壁将硫酸缓缓加入水中,边加边搅拌;

C、蒸发溶液是,要用玻璃棒不断地搅拌,防止液体飞溅;

D、在检查装置的气密性时,先将导管放入水槽中,然后用手握住试管外壁.

解答:解:A、给液体加热时,注意先预热,试管与桌面成约45°角,图中操作正确,故A正确;

B、稀释浓硫酸时,将水沿容器内壁缓缓注入浓硫酸中,会沸腾溅出,可能伤人.图中操作错误,故B错误;

C、蒸发溶液是,要用玻璃棒不断地搅拌,图中操作正确,故C正确;

D、在检验装置的气密性时,利用的是装置内气体的压强改变,有气泡冒出时,说明装置气密性良好,否则气密性不好,图中操作正确,故D正确.

故选B.

点评:掌握检验装置的气密性的方法,了解稀释浓硫酸和蒸发的方法,掌握给试管里的液体加热的注意事项.

阅读理解

Baths and bathing have been considered of an important medical therapy to man. In Greece there are the ruins of a bath tub and water system built over 3 000 years ago. The Romans had warm public baths. In some public baths as many 3 000 persons could bathe at the same time.

Treating diseases by bathing has been popular for centuries. Modern medical bathing, or hydrotherapy, first became popular in Europe and by the late 1 700’s also became popular in the United States.

For many years frequent bathing was believed to be bad for one’s health. Ordinary bathing just to be clean was avoided, and perfume(香水) was used to cover up body and smell.

By the 1 700’s doctors began to say that soap and water were good for health. They believed that it was good for people to be clean. Slowly, people began to bathe more frequently.

In the United States ordinary bathing was slow to become popular. During the 18th and early 19th centuries, many Americans were known as “the great unwashed”. In one American city, for example, a person could only take a bath every 30 days! That was a law.

Frequency of bathing today is partly a matter of habit. People know that bathing for cleanliness is important to health. Doctors know that dirty bodies increase that chance of disease.    

Therefore in the United States people generally bathe often.

1.What does the word “hydrotherapy” underlined in the second paragraph refer to?

A.A bathing tub.            B.Medical bathing.

C.Ordinary bathing.           D.Warm public baths.

2.Until when did doctors believe that ordinary bathing was good for health?

A.Until the 16th century     B.Until the 17th century.

C.Until the 18th century.    D.Until the 19th century.

3.Where did the ordinary bathing first become popular according to the passage?

A.In Africa.        B.In Europe.      

C.In the USA.            D.The passage doesn’t tell us.

4.Which of the following statements is not true?

A.Bathing was important to Greeks and Romans.

B.The Greek built water systems.

C.The Greek had warm public baths.

D.The Greek used bath tubs.

5.The passage is mainly about ______.

A.bathing in the USA

B.the good points and bad points of bathing

C.the history of bathing

D.the modern medical bathing

单项选择题