问题 选择题

过氧化氢与硫酸酸化的高锰酸钾溶液进行反应生成硫酸钾、硫酸锰、水和氧气。如果过氧化氢中的氧原子是示踪原子(18O),当反应完成后,含有示踪原子的物质是        (   )

A.硫酸钾

B.硫酸锰

C.氧气

D.水

答案

答案:C

本题考查氧化反应、还原反应的概念,二者同时发生。在反应中,高锰酸钾中+7价的Mn被还原生成硫酸锰中+2价的Mn,同时过氧化氢中-1价的O将被氧化生成0价的O,所以其氧化产物是氧气(18O2)。

阅读理解

阅读理解

     Do you know Australia? Australia is the largest island in the world. It is a little smaller than China. It

is in the south of the earth. Australia is big, but its population is not large. The population of Australia is

nearly as large as that of Shanghai.

     The government has made enough laws to fight pollution. The cities in Australia have got little air or

water pollution. The sky is blue and the water is clean. You can clearly see fish swimming in the rivers.

Plants grow very well.

       Last month we visited Perth, the biggest city in Western Australia, and went to a wild flowers'

exhibition. There we saw a large number of wild flowers we had never seen before. We had a wonderful

time. Perth is famous for its beautiful wild flowers. In spring every year Perth has the wild flowers'

exhibition. After visiting Perth, we spent the day in the countryside. We sat down and had a rest near a

path at the foot of a hill. It was quiet and we enjoyed ourselves. Suddenly we heard bells ringing at the

top of the hill. What we saw made us pick up all our things and run back to the car as quickly as we

could. There were about three hundred sheep coming towards us down the path. 

     Australia is famous for its sheep and kangaroos(袋鼠). After a short drive from any town, you will

find yourself in the middle of white sheep. Sheep, sheep, everywhere are sheep.

1. Australia is ________.

A. the largest country in the world

B. as large as Shanghai

C. not as large as China

D. the largest island in the north of the earth

2. The government had made ________.

A. few laws to fight pollution

B. so many laws that it can fight pollution

C. enough laws that it can hardly fight pollution

D. enough laws because the pollution is very serious

3. Which of the following is NOT true?

A. Perth is famous for its beautiful wild flowers.

B. Perth is bigger than any other city in Western Australia.

C. Perth lies in the west of Australia.

D. No other city is larger than Perth in Australia.

4. Which of the following is TRUE?

A. Australia is famous for its sheep, kangaroos and wild flowers.

B. We ran back to the car because we were in the middle of white sheep.

C. Three hundred sheep came towards us because they saw us.

D. If you go to the countryside in Australia, you will see a large number of white sheep.

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