7.4 解决办法的属性
Section outline
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Why hasn’t the ocean water in this photo turned to ice? The water in the glacier on shore is frozen , but the water in the ocean is still in a state.
::为什么这张照片中的海水没有变成冰呢? 岸上的冰川水是冰冻的,但海洋的水仍然处于一个状态。Q: What is it about ocean water that keeps it from when the falls below the freezing point of pure water?
::问:当海水坠落到纯净水的冰点以下时,A: Ocean water is salty.
::A:海洋水是咸的。How Solutes Affect Solvents
::溶剂如何影响溶剂Salt water in the ocean is a solution. In a solution, one substance, called the solute , dissolves in another substance, called the solvent . In ocean water, salt is the solute and water is the solvent. When a solute dissolves in a solvent, it changes the of the solvent. In particular, the solute generally lowers the freezing point of the solvent, which is called freezing point depression, and raises the point of the solvent, which is called . For example, adding either salt to water lowers the freezing point and raises the boiling point of the water.
::海洋中的盐水是一种溶液。在溶液中,一种物质,叫做溶液,溶解于另一种物质,叫做溶剂。在海水中,盐是溶液,水是溶剂。溶液溶解于溶剂中,溶液就会改变溶剂。特别是溶液一般会降低溶剂的冷点,即冷点压,并会提高溶剂的点,即溶剂。例如,在水中添加盐会降低冷点,提高沸点。Freezing Point Depression
::冻结点萧条Pure water freezes at 0 °C, but the salt water in the ocean freezes at -2.2 °C because of freezing point depression. We take advantage of the freezing point depression of salt in water by putting salt on ice to melt it. That’s why the truck in the Figure is spreading salt on an icy road.
::纯水冻结在0°C,但海水中的盐水冻结在-2.2°C,因为冷点压抑。 我们利用水中盐的冷点压抑,在冰上加盐来融化它。 因此,图中的卡车在一条冰冷的道路上撒盐。Did you ever see anyone add a fluid to their car radiator? The fluid might be antifreeze, like in the Figure . Antifreeze is mixed with water in the radiator to create a solution with a lower freezing point. This allows the radiator to function at a greater range of temperatures, even below 0 °C. For example, a 50 percent antifreeze solution won’t freeze unless the temperature goes below -37 °C.
::你有没有看到有人在汽车散热器中添加液体?液体可能是抗冻剂,如图所示。防冻剂与散热器中的水混合,以产生一个低温点的溶液。这让散热器在更大的温度范围内运行,甚至低于0°C。例如,50%的抗冻剂溶液不会冻结,除非温度低于-37°C。Boiling Point Elevation
::沸点升高Antifreeze could also be called “antiboil” because it also raises the boiling point of the water in a car radiator. Hot weather combined with a hot engine can easily raise the temperature of the water in the radiator above 100 °C, which is the boiling point of pure water. If the water boils, it could cause the engine to overheat and become seriously damaged. However, if antifreeze has been added to the water, the boiling point is much higher. For example a 50 percent antifreeze solution has a boiling point of 129 °C. Unless the water gets hotter than this, it won’t boil and ruin the engine.
::防冻剂也可以被称为“防冻剂 ” , 因为它在汽车散热器中也提高了水的沸点。 热天气加上热引擎可以很容易地将热水温度提升到100°C以上,也就是纯水的沸点。 如果水沸腾,可能会导致发动机过热并严重受损。 但是,如果在水中添加了防冻剂,那么沸点会高得多。 例如,50%的防冻溶液的沸点为129°C。 除非水比这更热,否则它不会沸腾和破坏发动机。Summary
::摘要-
When a solute dissolves in a solvent, it changes the physical properties of the solvent.
::当溶剂溶解溶解时,溶液会改变溶剂的物理特性。 -
A solute generally lowers the freezing point of a solvent, which is called freezing point depression. For example, spreading salt on an icy road melts the ice.
::溶液一般会降低溶剂的冷点,即冷点抑郁症。 比如,在冰冷的道路上撒盐会融化冰。 -
A solute generally raises the boiling point of a solvent, which is called boiling point elevation. For example, adding antifreeze to the water in a car radiator prevents the water from boiling.
::溶液通常会提高溶剂的沸点,即沸点高度。例如,在汽车散热器中添加防冻剂,防止水沸。
Review
::回顾-
What is freezing point depression?
::什么是冷点抑郁症? -
Give an example of boiling point elevation.
::举一个沸点高地的例子。 -
Assume you are going to boil water to cook spaghetti. If you add salt to the water, how will this affect the temperature at which the water boils? How might it affect the time it takes the spaghetti to cook?
::假设您要煮水煮意大利面。 如果您在水中加盐, 这将如何影响沸水的温度? 它会如何影响意大利面煮饭的时间?
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When a solute dissolves in a solvent, it changes the physical properties of the solvent.
