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Degree of dissociation accurately defined

  1. Apr 13, 2014 #1
    Is the degree of dissociation the value of

    Alpha when the dissociation begins with 1 mole of the solute, or is it alpha when the solute is 1 mole at equilibrium,



    There isn't a difference since I'm talking about very weak electrolytes but I want to know the accurate answer.
     
  2. jcsd
  3. Apr 14, 2014 #2

    Borek

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    Degree of dissociation is a fraction of substance that dissociated, and it doesn't depend on the amount of substance dissolved.
     
  4. Apr 14, 2014 #3

    It's said on Wikipedia that is the value of dissociated moles per 1 mole,

    It is meant one mole at equilibrium or when the dissociation begins with that 1 moles ?
     
  5. Apr 14, 2014 #4

    Borek

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    I don't care about what wikipedia says. Degree of dissociation is a fraction of the substance that dissociated. You start with n moles, m moles dissociate, degree of dissociation is m/n.
     
  6. Apr 14, 2014 #5

    Ok, m/n will give the value of m when n is 1, there's no contradiction
     
  7. Apr 14, 2014 #6

    Borek

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    No contradiction, but a lousy thinking. Ratio doesn't require referring to the amount of substance.
     
  8. Apr 14, 2014 #7

    "n moles" is the number of moles at equilibrium or the number of moles that the dissociation starts with ???
     
  9. Apr 15, 2014 #8

    DrDu

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    The degree of dissociation can be defined independently of equilibrium.
    E.g., you could measure it as a function of time after bringing an undissociated substance into a solvent.
     
  10. Apr 15, 2014 #9

    Borek

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    Perhaps it is time you start paying attention to what you read.
     
  11. Apr 15, 2014 #10

    I'm sorry, thanks a lot for you help
     
  12. Apr 15, 2014 #11
    I have a question about the ionic product of water

    How is Kw = [ H ] [ OH ] = 10^-14 mole/ liter derived.
     
  13. Apr 15, 2014 #12

    Borek

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    It is not derived, it is determined experimentally.

    Please start new threads for new questions.
     
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