Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Ketap on September 08, 2014, 08:20:03 AM
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hi, i am new here..glad to found this forum..if u don't mind,i want to ask all..i know this is quiet stupid question..but i really having hard time to understand this..
it is said that in higher altitude, we will get lower boiling point (Ex 92 0C) than at sea level (ex 100 0 C)..but why do we need to cook longer in the higher altitude? i don't get it..if we get lower boiling point..isn't it easier to boil something (and faster cooking) in higher altitude?
please help, thank u :)
regard,Ketap
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The reactions that take place during cooking happen more slowly at lower temperature, therefore if you cook at altitude in boiling water at 92°C, it will take longer than at sea level in boiling water at 100°C. It is temperature, not the physical act of boiling, that cooks food. (That is the point of a pressure cooker - by applying high pressure, the boiling point of water increases, so cooking occurs at higher temperature and thus is faster.)
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Just think, if you really evacuate the pressure above the pot of boiling water, you can get water to boil at very low temperatures, even room temperature. Think . how does holding food at room temperature cook it, even if its boiling?
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Mate,
During cooking our food our aim is to cook our food not to evaporate the water....
Many components of food is only get cooked due to hot water....
since water can easily penetrate it deeply...if the whole water is get evaporated.. Then how will it get cooked..
I am going to giving an example which likely to be related to this...
See....
Usually reactions depends kinetically upon the phase in which it is taking place...
An example from Organic Chemistry...
For the formation of Grignard Reagent from aryl Fluoride and aryl Chloride(It need a high temperature)
We use THF(tetra hydro-furan) instead of di-ethyl Ether...
Since ether have much lower Boiling point....so before the completion of the reaction ether get evaporated.. That why we use THF..
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Think of water as a medium to transfer heat. Hotter the medium faster the cooking.
Think of the BP as the limit to how hot the medium can get without being "destructed".
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The higher the altitude is gonna be the air pressure gonna decrease. Does that ring any bell?
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I suppose if the O.P. ever bothers to come back, they'll be able to figure it out from the multiple ways of looking at the problem we've all offered. :D