问题 选择题

水是生命之源,我们的日常生活和工农业生产都离不开水.下面关于水的叙述不正确的是(  )

A.水在自然界中的循环为物理变化

B.利用活性炭的吸附作用净化水为化学变化

C.用生石灰去除室内潮气为化学变化

D.水通直流电得到氧气、氢气为化学变化

答案

A、水在自然界中的循环过程中没有新物质生成,为物理变化.正确

B、利用活性炭的吸附作用净化水的过程中没有新物质生成,为物理变化.错误;

C、生石灰和水反应能生成氢氧化钙,属于化学变化. 正确;

D、水通直流电得到氧气、氢气为化学变化. 正确.

故选B.

阅读理解

第三部分:阅读理解(共20小题,每小题2分,满分40分)

阅读下列短文,从每题所给的四个选项( A、B、C、D )中,选出最佳选项,并在答题卡上将该项涂黑。

A Businessman ordered ten goldsmiths to make ten coins each. Each coin was to weigh exactly ten gram of pure gold.

One of the goldsmiths was a bad man.  He decided to cheat.  He made all his coins one gram short. Now the businessman heard that one of them had cheated.  He also  heard that this man had made each of his coins one gram short.

The businessman was a clever person.  He took a certain number of coins from each of the smiths,  weighed them together once only and found their weight to be 540 grams. This was enough for him to find out which one of the goldsmiths had cheated.

1 The word “goldsmith” means        .

A. a person named Smith who sells articles(物品) made of gold

B. a thief who steal gold

C. a worker who makes articles of gold

D. a person who works for the man named Smith

2 The businessman found the cheat by        .

A. looking each man in the eye

B. weighing one coin after another

C. weighing coins

D. asking who hadn't made coins according to his request

3 In order to find the cheat,  the businessman weighed      coins altogether .

A. fifty      B. fifty-four    C. fifth-five        D. sixty

4 Suppose the businessman took one coin from the first smith,  two from the second, 

and ten from the tenth,  he found out that he      goldsmith was the cheat.

A. first      B. sixth       C. ninth                 D. tenth

问答题 简答题