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More emphasis .

  1. May 31, 2005 #1
    More emphasis.....

    I understnad that atompsheric pressure affects boiling point and that as atmospheric pressure increases, boiling point increases....but why?
  2. jcsd
  3. May 31, 2005 #2


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    Super reduced/no frills version:

    Think of a large column of air resting on top of the water trying to boil. In order for the water to be boiling, some of the molecules have to have enough energy to overcome the atmospheric pressure to escape from the water (don't forget a higher pressure will result in a higher density). So a higher pressure would mean a molecule would have to have more energy to break free into the more dense atmosphere, i.e. the water needs a higher temperature. A lower atmospheric pressure means the molecules don't need as much energy.

    If you want to start talking about hydrogen bonding and vapor pressure we can. Check out this web site, it may help:http://www.elmhurst.edu/~chm/vchembook/163boilingpt.html [Broken]
    Last edited by a moderator: May 2, 2017
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