8/11/12

Boiling



When the liquid temperature was raised, will be reached a certain point when the liquid begins to boil. Boiling can be interpreted evaporation that occurs in the entire liquid contents, not just on the surface only. Vapor bubbles are formed inside the liquid. The bubbles will rise and break through the surface.

The occurrence of boiling can be accelerated by raising the temperature or by lowering the pressure. Rise in pressure will increase the boiling point. Conversely, if the pressure is reduced, the boiling point will be low. In high places, the lack of atmospheric pressure so that the boiling point in the area will be low so as to make the cooking process to be more slow and difficult.

Reduction pressure low boiling point allows much practical use in the field of vacuum evaporation (evaporation at low pressure) process is very important in the sugar industry. Boil the water coming out from liquid at normal atmospheric pressure would scorch the sugar. In the vacuum evaporation, the pressure is made so low that the water can be removed with that relatively lower temperature

The amount of heat required for convert a unit mass of liquid into vapor at the boiling point of substances called heat vaporization. Each object has a heat vaporization of each. For example, almost 540 calories required for vaporize one gram of water at a temperature of 100 degrees centigrade. and in the case of ethyl alcohol is required only 204 calories



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