Talk:Nernst equation

message: 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?
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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!!!
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: 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)
replies: text: The factor 2.303 is simply a conversion factor between log and ln.  This is just elementary maths, nothing physical. 2A01:E0A:149:BEB0:AC1A:5DE6:A752:EE86 (talk) 11:43, 6 May 2022 (UTC)

text: The form of the equation and the derivation is unclear and lacks utility as a reference. While I can follow it, it just isn't useful for common application. Frankly, the equation form has sacrificed readability for generality. A simpler form of the equation should be moved to the top of the section and a detailed derivation of a general form should be lower down. ZakNo (talk) 13:12, 28 January 2021 (UTC)
thread_title: Form of the equation

message: 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)
thread_title: Biological membrrane

message: 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)
thread_title:  Activities not Concentrations 

message: This was alluded to by Olin and Confuseddave above, but I think there remains unresolved issues with the first equation in the article, which would be fixed by replacing \frac{a_{\mbox{Red}}}{a_{\mbox{Ox}}} by Q, the reaction quotient.
According to the (intro) chem that I know, this equation is a valid way to write the Nernst equation:
:
E = E^0 - \frac{RT}{zF} \ln Q
But I'm less sure about
:
E = E^0 - \frac{RT}{zF} \ln\frac{a_{\mbox{Red}}}{a_{\mbox{Ox}}}
For example, take the reaction
:CATHODE: solid-A + electrons --> anion-A
:ANODE: anion-B --> solid-B + electrons
Then the reduced species is [red]=[anion-A], and the oxidized species is [ox]=[anion-B], and clearly Q=[red]/[ox]. So no problem here; this case works.
But now suppose instead we have:
:CATHODE: Cation-A + electrons --> solid-A
:ANODE: solid-B --> Cation-B + electrons
then the oxidized species is [ox]=[cation-B] and the reduced species is [red]=[cation-A].
Then Q = [cation-B]/[cation-A], but [red]/[ox]=(1/Q)!
Therefore, I propose switching the equation in the intro of the article to the version with Q, and taking out the version with [red]/[ox] altogether. Unless I'm confused. Thanks! --Steve (talk) 23:56, 4 May 2008 (UTC)
replies: text: UPDATE 2: Having heard no objections in the last week, I've edited the intro accordingly. Comments? --Steve (talk) 04:09, 13 May 2008 (UTC)
thread_title:  More on Q versus [red]/[ox] 

message: This page would be made clearer with an example calculation. 58.6.101.63 (talk) 01:01, 29 October 2008 (UTC)
replies: text: And also it could list the reverse potential of the 4 most abundant ions in neurons at rest. XApple (talk) 00:32, 12 January 2009 (UTC)
thread_title:  Example Calculation 

message: What is the reference for the Nernst_equation#Nernst_potential? Is it the inside potential with respect to the outside or vice versa? 
Bless sins (talk) 23:05, 6 October 2010 (UTC)
thread_title:  Sign 

message: I find it weird that the equation for the half-cell reduction potential is written like this:
:
E_\text{red} = E^{\ominus}_\text{red} - \frac{RT}{zF} \ln\frac{a_\text{Red}}{a_\text{Ox}}
 
Because it says that a_\text{Red}  stands for 'activity of the reductant' and  a_\text{Ox} for 'activity of the oxidant'. This is strange because the equation refers to only half of a redox reaction, which means only the reductant OR the oxidant is present. It would be clearer if the article made reference to a model reduction half-reaction:
Ox + n electrons --> Red 
Also, in the first statement of this article:  "Nernst equation is an equation that can be used (in conjunction with other information) to determine the equilibrium reduction potential of a half-cell in an electrochemical cell" shouldn't it say that the Nernst equation can be used to determine the potential of a half-cell, be it at equilibrium or not?
 — Preceding unsigned comment added by 178.199.110.247 (talk) 21:32, 30 November 2011 (UTC)
thread_title:  Notation for the activities 

message: From the beginning the equation was based on a implausible concept used by the author that beeing the dissolution pressure of metals which had astronomically high values--5.15.176.81 (talk) 15:50, 29 September 2013 (UTC)
thread_title:  Original derivation and history 

message: I introduced the term "unpoised electrode" which I found in internet, but I'm not a chemist. A professional look would be welcome (if this is a commonly used term). Perhaps some link to kinetic equation would be nice in this point ("other effects" mentioned in the article). Also probably so called "anodic index" is related to this section - see galvanic corrosion article.  — Preceding unsigned comment added by 159.205.140.205 (talk) 20:34, 3 November 2013 (UTC)
thread_title:  Limitations 

message: Electron concentration is missing from the the equation of the redox reaction. Shouldn't it be present?--5.2.200.163 (talk) 17:42, 20 November 2015 (UTC)
thread_title:  Concentration of electrons 

message: The value for R, the universal gas constant, is different from that quoted on the gas constant page. There is likely a simple explanation for this discrepancy.  — Preceding unsigned comment added by GeoffreyZanders (talk • contribs) 03:34, 21 March 2016 (UTC)
thread_title: Gas constant value

message: Is this equation a logical consequence of the ideal gas law?--213.233.84.55 (talk) 15:15, 11 August 2018 (UTC)
thread_title:  Connection to ideal gas law 

message: Using the Wikipedia app with Android 10 Q in a Pixel XL, white text on black ground, some math. expressions are invisible. Will try to get specifics. Problem appears in other, unrelated articles.
nikevich Nikevich 14:26, 2 January 2022 (UTC)
replies: text: More about "black on black":
The first such instance of "b. on  b."" follows the text that says,
"...Gibbs free energy ΔG is related to the free energy change under standard state ΔGo by the relationship:"
One void, later in the article, extends over most of the screen in portrait mode.
Problem is really likely to be unsupported rendering of the specific format of this type of math display. White text on a black ground might not be accounted for.
I'm sorry, at age 85, my energy is limited, else I'd follow up, further.
Best regards,
nikevich Nikevich 15:01, 2 January 2022 (UTC)
thread_title:  "Black on black" invisible equations