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Homework Help: Electrode potentials

  1. May 5, 2006 #1
    When we work out the E cell of with the electrode potential values of Zinc and copper (for example) Why does a positive E cell value indicate that the reaction is plausible?
  2. jcsd
  3. May 6, 2006 #2


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    Staff: Mentor

    Matter of convention.
  4. May 6, 2006 #3


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    [tex]- \Delta G^0 = work~done ~at~constant~potential=E^0_{cell} \Delta Q [/tex]
    [tex]\Delta Q = nF [/tex]
    [tex]\implies \Delta G^0 =-nFE^0_{cell} [/tex]

    Of course, now this translates to another convention : that a negative free energy change tells you that the reaction is plausible. To make this more intuitive, it may help to go a step further.

    [tex]\Delta G^0 = -RT lnK [/tex]
    [tex]\Delta G^0 < 0 \implies lnK > 0 \implies K > 1 [/tex]
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