问题 填空题

下图是A、B两种固体物质的溶解度曲线。

(1)P点的含义是____________________;

(2)t2℃时,将60gA物质放入100g水中充分溶解所得溶液为_______(填“饱和”或“不饱和”)溶液,其质量为_______g;

(3)若将A物质从A和少量B的混合溶液中分离出来,宜采用的提纯方法是__________;

(4)将t2℃ A、B两种物质的饱和溶液降温到t1℃时,溶质质量分数关系为A______B。

答案

(1)t1℃时,A、B两种物质的溶解度相等

(2)饱和;150

(3)冷却热饱和溶液(或降温结晶)

(4)>(或大于)

单项选择题
阅读理解

阅读理解。

     In Kansas City, Missouri, a computer helps firefighters. The computer keeps information about every one

of the 350 000 street addresses in the city. When firefighters answer a call,the computer will give them

important information about the burning building: its position, size and so on. In fact, the computer system has

a lot of ways of helping firefighters with the problems facing them. For example, it can give medical information about invalids (伤残者) living in a burning building. With this information, the firefighters can take special care

to find these sick persons and save them. The Kansas City computer system also keeps a medical record of

each of the city's 900 firefighters. This kind of information is especially useful when a fireman is injured. With

this medical information, doctors can treat the injured firefighters more quickly and easily.

     The firefighters themselves need the computer's help. They know about possible dangers and prepare for

them. Many times the computer information helps to save lives and property. Sometimes the lives are those of

firefighters themselves!

1. Missouri is most likely the name of _____.

A. a street where firefighters work

B. a city smaller but more famous than Kansas

C. one of the states of America

D. the centre of the computer system

2. The computer can give ____.

A. all useful information about the city

B. good information about everybody in the city

C. useful information about every street address in the city

D. nice pictures about each building on fire

3. The computer system can _____.

A. give the firemen important help in many ways

B. have a few ways of helping the firefighters

C. hardly give any useful information for the firefighters

D. put out every fire quickly and safely

4. The firefighters know that the invalids in a burning building _____.

A. will not save themselves

B. want information from the computer

C. cannot see the dangers

D. need special help