1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Determining the potential in a cell that is not at equilibrium concentrations.

  1. Dec 2, 2011 #1
    1. The problem statement, all variables and given/known data
    I attached a picture and I am confused by Part C.
    The standard potential is given Eo=1.21


    2. Relevant equations
    Ecell=Eocell-RTlnQ/nF
    R=8.3145
    T=298.15
    F=96485
    Q=activity products/ activity reactants

    3. The attempt at a solution
    My problem with this question is finding Q.

    Fe(s) -> Fe2+(aq) + 2e-
    Fe3+(aq) + e- -> Fe2+(aq)

    Balanced equation (is this right?):
    2Fe3+(aq) + Fe(s) -> 3Fe2+(aq)


    As suggested in the problem, the [Fe2+] of both half cells are different. Thus I do not know how to set up my Q, assuming that my balanced equation is correct.
     

    Attached Files:

  2. jcsd
  3. Dec 5, 2011 #2

    Borek

    User Avatar

    Staff: Mentor

    You can derive overall Nernst equation for the system starting with separate Nernst equations for each half cell. Just assume two separate potentials for each half cell initially, and combine them in the final equation - this will be the potential given as a standard one.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Determining the potential in a cell that is not at equilibrium concentrations.
Loading...