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问题 填空题

学校为同学供应开水，用锅炉将200千克水从25℃加热到100℃，燃烧了6千克煤[水的比热容是4.2×103J/（kg?℃），煤的热值是3.4×107J/kg ]试求：

（1）200千克水吸收的热量？

（2）6千克煤完全燃烧放出的热量？

（3）此锅炉的效率？

答案

（1）6.3×107J（2）2.04×108J（3）31％

阅读理解

Read and judge the sentences. (读短文，判断下列每个句子是否正确)

     This is a beautiful forest (森林) and it is very big，too. There are many tall trees in the forest. Lucy

and Joyce are in the forest now. They can see two birds and two turtles(乌龟). The big bird is a

peacock. It is beautiful. The small bird is very lovely. The old turtle has a stick in his hand and the young

turtle has a short tail. Lucy and Joyce are very happy.

( ) 1. The forest is beautiful and big. 

( )2. There are two big birds in the forest.

(     )3. The old turtle has a stick in his hand.

(     )4. The big bird is a peacock.

(     )5. Lucy and Joyce are very happy in the forest.
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选择题

下列说法中正确的是 ( 　    )

A．冰在0°C时一定会熔化，因为0°C是冰的熔点

B．液体蒸发的快慢与液体温度的高低有关

C．0°C的水，其内能也为零

D．冬天看到嘴里吐出“白气”，这是汽化现象
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