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Homework Help: AS Chemistry help

  1. Oct 31, 2008 #1
    Hi, this question is really bugging me.
    Thanks in advance.

    1. The problem statement, all variables and given/known data

    The difference between the enthalpy change of combustion if sucessive chain alkanes is around -650 kJ/mol

    2. Relevant equations

    Why does the value of enthalpy change of the sections of the chains have a different value...

    That wasn't very clear was it?

    3. The attempt at a solution

    http://img516.imageshack.us/img516/5919/whyqf0.jpg [Broken]
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Oct 31, 2008 #2


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    Science Advisor
    Homework Helper

    For one calculating the the enthalpy of a reaction using tabulated bond enthalpies is an estimation - the context around which the bond is situated may alter its common bond enthalpy. E.G. You may have utilized the bond enthalpy of the carbon hydrogen bond in methane however note that your current molecule is relatively unstable ... its been a while since I've faced this topic so the actual answer may be related to a distinctly unrelated matter.
    Last edited by a moderator: May 3, 2017
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