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  3. When the temperature of a liquid is raised enough, the liquid boils. This means that bubbles of vapor, containing millions of mo

When the temperature of a liquid is raised enough, the liquid boils. This means that bubbles of vapor, containing millions of mo

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问题     When the temperature of a liquid is raised enough, the liquid boils. This means that bubbles of vapor, containing millions of molecules, form below the surface. In order for such bubbles to be produced, the pressure of the vapor inside them must be equal to the pressure of the air upon the surface of the liquid. If the air pressure is greater, the bubble will collapse. The boiling point of a liquid, then, is the temperature at which the vapor pressure of the liquid is equal to the atmospheric pressure upon the liquid at the surface.
    The pressure of the atmosphere at sea level is about one kilogram per square centimeter. We call this pressure one atmosphere. The boiling point of a liquid, therefore, is the temperature at which its vapor pressure equals one atmosphere. The boiling point of water is 100 Celsius; of ethyl alcohol 78.5 Celsius; of mercury, 356.9 Celsius.
    If the pressure on the surface of the water is reduced, the boiling point will be lower. Now the higher up we go from sea level, the lower the atmospheric pressure becomes, since there is less air to press upon us. Hence, while water boils at sea level at a temperature of 100 Celsius, its boiling point on a mountain three kilometers high is only 90 Celsius. Since the temperature of water does not rise as a result of boiling, it would take you longer to cook potatoes or carrots in boiling water on the mountain than it would at sea level.
Which statement of the following is false according to the passage?
选项 A、The boiling point of water on a mountain three kilometers high is only 90 Celsius.
B、It would take you longer to cook potatoes in boiling water on the mountain than it would at sea level.
C、When the temperature of a liquid is raised enough, the liquid boils.
D、The boiling point of water on a mountain six kilometers high is 95 Celsius.
答案D
解析 本题为是非判断题。在第三段最后提到“…while water boils at sea level at a temperature of l00 Celsius，its boiling point on a mountain three kilometers high is only 90 Celsius．Since the temperature of water does not rise as a result of boiling，it would take you longer to cook potatoes or carrots in boiling water on the mountain than it would at sea level．(……水的沸点，在海平面处是100度，而在三千米高的山上只有90度。由于沸腾后水的温度不会上升，于是要烧熟土豆或胡萝卜，在山上比在海平面处需要更长的时间。)”可以判断A和B是正确的。在文章一开始提到“When the temperature of a liquid is raised enough，the liquid boils．(当液体温度升高到一定程度，该液体就沸腾了。)”可以判断C是正确的。用排除法，可以得出结论。另外，在第三段中提到“… while water boils  at  sea level at a temperature of 100  Celsius，its boiling point on a mountain three kilometers high is only 90 Celsius．(……水的沸点，在海平面处是100度，而在三千米高的山上只有90度。)”根据这个方法计算，海拔三千米的水的沸点是90度，那么，海拔六千米的水的沸点就应该是80度。
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