Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Electrochemical cells

  1. Nov 21, 2011 #1
    1. The problem statement, all variables and given/known data
    Based on the following chart, what ions would you use to construct an electrochemical cell with potential closest to 2.00 V?

    [PLAIN]http://img546.imageshack.us/img546/5568/electrochemicalcellchar.png [Broken]

    2. Relevant equations
    I know that I am supposed to add the voltages of the 2 reactions but I am not sure how the signs would go. We are not using a textbook for this class so I have nothing to reference.

    3. The attempt at a solution
    I'd use the following reactions and voltages
    Fe3+ -> Fe2+ (-0.771 gaining electron)
    Na (s) -> Na+ (+2.71 losing electron)

    so the cell voltage would be 1.94V. Is this correct?
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Nov 21, 2011 #2


    User Avatar

    Staff: Mentor

    Think about simple math - what is the distance between -2.7 and +0.7 points?
  4. Nov 21, 2011 #3
    Thank you, that was very helpful!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook