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Homework Help: Calculate The Cell Potential

  1. Mar 30, 2012 #1
    1. The problem statement, all variables and given/known data

    Calculate the cell potential (ECell) of an electrochemical cell with Mg/Mg^2+, and Fe/Fe^2+ electrodes. [Mg^2+] and [Fe^2+] = 1.00 M.

    Fe^2+(aq) + 2e^- --> Fe(s) = -0.45V
    Mg^2+(aq) + 2e^- --> Mg(s) = -2.37 V

    a) 1.90
    b) 1.92
    c) 1.94
    d) 2.82
    e) 2.80

    2. Relevant equations

    ECell = EReduction + EOxidation

    3. The attempt at a solution

    I believe the answer is B as I believe because the Mg having a lower value of V will have it's sign changed to form a positive value (oxidation). Is this correct?
  2. jcsd
  3. Mar 30, 2012 #2


    User Avatar

    Staff: Mentor

    It is not about changing a sign. It is a about a distance between the half cell potentials - mark them on the number axis and it will be obvious.

    Doesn't mean your answer is incorrect.
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