Talk:Nernst equation

From Wikipedia, the free encyclopedia

You have new messages (last change).
This article needs more context around or a better explanation of technical details to make it more accessible to general readers and technical readers outside the specialty, without removing technical details. See below for more information.


This is not a particularly elegant layout for the equation .... can anyone improve on it? David Martland 09:47 Dec 5, 2002 (UTC)

My chemistry textbook, Zuhmdal's Chemistry (third edition) seems to disagree with this equation, listing instead of "[red]/[ox]" the reaction quotient Q, which is equal to [red]^x/[[ox]^y, where x and y are the coefficients of the reduced species and the oxidized species, respectively, in the balanced redox reaction.

Am I simply misanalyzing something?

<<Next comment>> I've been seing variations in the Nernst equation. Some using log functions and some using ln functions. Also I've seen one where everything gets multiplied by 2.303 and I don't know which if any of them is correct!!! <</End comment>>

2.303 ~ 1/log_10(e) . This comes from the change of base of the log from e to 10. Ash Lightfoot 04:23, 14 March 2006 (UTC)

I agree with the comment that the equation should have Q above instead of concentrations. The concentrations imply that there are no protons in the redox equation, and that only one species of each half reaction is an ion. This does not have to be true. The use of Q is much more general. Olin 13:49, 17 March 2006 (UTC)

The equation for biological membranes is misleading in two ways: - We normally express the Nernst equation at 37 degrees C rather than room temperature - It's ONLY [out]/[in] when you are considering CATIONS. If you're considering the effect of anions like chloride, you use [in]/[out].

Will update when I have time to check out my sources

Confuseddave 09:27, 8 February 2006 (UTC).

[edit] Activities not Concentrations

The Nernst Eq'n is first given with activities and then concentrations. The two are not equivalent, except at very high dilution. I believe the formulation with activities is correct, although the Nernst equation is sometimes given with a formal electrode potential and concentrations rather than a standard electrode potential and activities. However, if concentrations are used the conditions under which the formal potential was measured must be stated (supporting electrolyte, concentration of ions, etc.) Can someone sort this out (with appropriate references)? Ahw001 13:27, 23 March 2006 (UTC)

For more details see external link Ahw001 07:55, 24 March 2006 (UTC)

[edit] Formal Electrode Potential?

Anyone have any idea what the formal electrode potential is? I can't find any mention of it anywhere else, and its not present in any of my text books. Olix 20:20, 13 September 2006 (UTC)

Try "Electrochemical Methods" by A.J. Bard and L.R. Faulkner or "A First Course in Electrode Processes" by D. Pletcher Ahw001 06:48, 28 September 2006 (UTC)

Retrieved from "http://en.wikipedia.org../../../n/e/r/Talk%7ENernst_equation_c946.html"