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!

Homework Help: Calculate cell potential when concentrations aren't 1M, but are the same.

  1. Nov 28, 2012 #1
    1. The problem statement, all variables and given/known data
    Calculate standard potential for a Cu2+ 0.5M, Zn2+ 0.5M cell.

    2. Relevant equations
    Ecell = E0cell - (RT/nF)lnQ

    3. The attempt at a solution
    So, I know at standard conditions it would simply be
    Ecell = 0.340 - (-0.763)
    Ecell = 1.103

    It's the concentrations that are confusing me. If they are the same and no half reactions are multiplied, I get a Q value of 1.
    lnQ = ln(1) = 0.
    So in this case does it not matter what the concentrations are as long as they are the same?
  2. jcsd
  3. Nov 29, 2012 #2


    User Avatar

    Staff: Mentor

    In this case potentials of both half reactions are shifted by the same amount, so the final result stays the same. It doesn't have to be always this way.
  4. Dec 3, 2012 #3
    Sorry for the delayed thank you, but thank you :)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook