问题 问答题

小亮的家庭化学实验室有如下物品:①试管②导管和橡皮塞③煤气和煤气炉④小苏打⑤筷子⑥铁钉⑦铜丝⑧食盐⑨食醋⑩石灰水(11)硫酸铜(12)水(13)柠檬酸(14)玻璃杯 请你与小亮一起完成如下实验:

(1)若要探究牙膏中是否含有碳酸钙,需要用到的物品是(填序号,注意仪器完整)______;

(2)若要探究铁钉锈蚀的条件,除上述物品外还需要的物品是______;

(3)若要利用上述物品证明铁的活动性比铜强,写出实验中发生的化学方程式______;

实验现象为______.

(4)除了进行上述三个实验外,利用上述物品,还可以完成的实验有(举二例)______.

答案

(1)若要探究牙膏中是否含有碳酸钙,可以用食醋能和碳酸钙反应生成能使石灰水变浑浊的气体二氧化碳的性质来检验,用到的仪器有试管、导管与橡皮塞,药品为食醋和石灰水.故填:①②⑨⑩.

(2)探究铁钉锈蚀的条件时,有时要防止氧气进入水中,这时可以在水中加入植物油,从而使氧气无法进入水中.故填:植物油.

(3)要证明铁的活动性比铜强,可以把铁放入硫酸铜溶液中,铁和硫酸铜反应能生成硫酸亚铁和铜,反应的化学方程式为:Fe+CuSO4=Cu+FeSO4.实验现象为铁丝表面出现一层紫红色的铜,溶液的颜色由蓝色变为浅绿色;

(4)探究加速食盐溶于水的某一方法的有效性.我选择的方法是加热,我的实验方案是:取适量相同质量的食盐,分别同时放入有相同水量的试管,将其中一个加热,比较观察食盐溶解情况;用石灰水可以检验人呼出的二氧化碳气体与空气中的二氧化碳含量高低.除进行上述实验外,只利用上述物品,还可以完成的实验有:探究加速食盐溶于水的某一方法的有效性或人呼出的二氧化碳气体与空气中的二氧化碳含量比较.

故答案为:

(1)①②⑨⑩;

(2)植物油;

(3)Fe+CuSO4=Cu+FeSO4;铁丝表面出现一层紫红色的铜,溶液的颜色由蓝色变为浅绿色;

(4)探究加速食盐溶于水的某一方法的有效性或人呼出的二氧化碳气体与空气中的二氧化碳含量比较.

阅读理解

阅读理解。

    One day, my mother and I went shopping at a Chinese supermarket. We found that the crucian carps

(鲫鱼) in the seafood counter were very fresh, as a result we chose four crucian carps and handed them

over to the seller. As it would take some time to clean the fish and dispose (处理) of their internal organs

(内脏), we decided to look around the other places first. When we came back to the seafood counter, I

asked the seller for my fish. He raised one, which was being cleaned, to let me have a look and tell me he

was still working on the fish. I hurriedly said, "Go ahead, Go ahead." I meant for him to go on.

    Unexpectedly, the seller stopped his work, looking at me with puzzled expression, and asked me in reply,

"Go ahead?" "Yes," I said, "go ahead". He pointed the fish in all seriousness, and repeated very seriously,

"Head?" Paying no more attention to him, I turned back to chat with my mother. Suddenly, "Bang, bang,

bang," was heard from the counter. Quickly, the seller passed the four fish without heads to me.

     I asked loudly, "Why did you cut all the heads off?" The seller was also very annoyed (颇为生气的)

and said, "Didn't you tell me to go ahead again and again?" On hearing what he said I felt funny as well

as angry. It turned out that he considered "go ahead" as "cut the head off". No wonder he asked me several

times about it!

    Taking the headless fish home, I became frightened. Wouldn't it be possible that the hairdresser would

have cut my head off if I had gone to get my haircut?

1. Where did the story happen? [ ]

A. In China.

B. On the beach

C. In a Chinese supermarket

D. At the hairdresser's

2. What does "Go ahead" mean in this passage? [ ]

A. Cut off the heads of the fish.

B. Go on to clean the fish.

C. Continue to walk.

D. Go around.

3. Why did the seller cut all the heads off? [ ]

A. Because I asked him to do so.

B. Because he wanted to cut off all the heads.

C. Because I told him to go ahead again and again.

D. Because he mistook what I said.

单项选择题