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Homework Help: Dependency of electrolyte conductivity to temperature?

  1. Sep 12, 2010 #1
    Hi, I'm new here.

    As I was designing my IB lab, this idea popped in my head: Although the electrical conductivity of metals (and other solids) decrease as temperature rises, what about electrolytes?

    For all I know, electrolytes conduct electricity by charged ions, which react with both electrodes, conducting electricity. As I've learned in my chemistry class, a higher temperature means more collision between these ions, speeding up reaction time.

    All this led me to think that electrolytes would conduct electricity better as temperature rises. I would really appreciate it if you guys can verify whether this is plausible as I do not want to design a pointless lab.

    Hi, I'm new here.

    As I was designing my IB lab, this idea popped in my head: Although the electrical conductivity of metals (and other solids) decrease as temperature rises, what about electrolytes?

    For all I know, electrolytes conduct electricity by charged ions, which react with both electrodes, conducting electricity. As I've learned in my chemistry class, a higher temperature means more collision between these ions, speeding up reaction time.

    All this led me to think that electrolytes would conduct electricity better as temperature rises. I would really appreciate it if you guys can verify whether this is plausible or am I totally off.

    Thanks a bunch
     
    Last edited by a moderator: Sep 13, 2010
  2. jcsd
  3. Sep 13, 2010 #2

    Borek

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    Staff: Mentor

    Conductivity of the solution and speed at which charge moves through the phase boundary are two separate things, I have a feeling you are trying to mix them - don't.

    But you are right that typically conductivity of the solutions increases with the temperature.

    --
     
  4. Sep 13, 2010 #3
    thanks for responding. I was indeed mixing up the two as I thought the faster/easier the charges move the more conductive a substance is.

    As that's not the case, can you explain why conductivity of electrolytes would increase as temperature increases? Also, I'd like to know wether this is a directly porportional (linear) relationship (over a limited temp. range), inversely proportional relationship, or some more exotic variant (power, polynomial, etc).
     
  5. Sep 14, 2010 #4

    Borek

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    Staff: Mentor

    Actually that's correct - but thats when the charge moves in bulk of the solution. Whatever happens at the electrodes doesn't matter. You must misunderstood my previous post - phase boundary is where the electrode (usually solid) meets with the solution (usually liquid). You have mentioned electrons entering the solution at the electrodes in our original post, that's the part I was referring to.

    There is no universal law describing the dependence. Sometimes it is linear, sometimes it can be nicely approximated by 2nd or 3rd degree polynomial.
     
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