Talk:Faraday constant

Standard form?

Is it worth giving more prominence to the value of the constant (and putting it in standard form)? St3f 13:05, 11 July 2007 (UTC)

Merged

I merged the contents of Faraday (unit) into this article, and changed the former into a redirect to here. There may still need to be clean-up done on the associated talk pages. | Loadmaster (talk) 20:02, 11 December 2008 (UTC)

I have copied then contents of Talk:Faraday (unit) below. Physchim62 (talk) 22:11, 11 December 2008 (UTC)

redirect?

Searching for "Faraday" should take the user to Michael Faraday. A faraday is a nondescript unit that no one uses any more, much less important than the physicist after whom it is named. --141.154.55.199 11:17, 14 November 2006 (UTC)

Redirected, page renamed "Faraday (unit)". --Saaska (talk) 12:03, 10 June 2008 (UTC)

You're right of course, but electrochemists are dumb asses enough to still use it...88.110.123.140 (talk) 23:07, 2 February 2012 (UTC)

Correct conversion to coulombs?

What is the correct conversion factor from faradays to coulombs? Faraday says 96485.3415, but conversion of units says 96485.3383. Is either one of these an "accepted" conversion value? (message posted to Talk:Faraday and Talk:Conversion of units.) --bdesham 13:56, 8 Apr 2005 (UTC)

Merged and redirected

I merged this page and changed it to redirect to Faraday constant. | Loadmaster (talk) 19:56, 11 December 2008 (UTC)

unmerging

I think that it would be better to have separate pages for the Faraday constant (measured in coulombs per mole) and the faraday unit (measured in coulombs). Nicole Sharp (talk) 09:35, 4 February 2020 (UTC)

Post-merge discussion

Faraday's constant HAS NOT been replaced by Coulombs. Faraday's constant IS A CONSTANT (a number), not a unit. The coulomb IS A UNIT, not a constant. Faraday's constant is 96485 Coulombs per mole!!!! How can it "replace" one its own units!

This is far too elementary a mistake even for Wikipedia.

Periololon (talk) 17:00, 27 May 2010 (UTC)

I haven't checked but maybe the sentence was mistakenly written when this article was merged into here? Anyway I fixed it now. --Steve (talk) 18:02, 27 May 2010 (UTC)

Exact Vaue

The exact value is: 96 485.3399(24) according to http://www.iupac.org/publications/ci/2011/3302/ci3302preprintXcoplen_101210.pdf Can someone clarify? — Preceding unsigned comment added by 74.247.199.50 (talk) 20:05, 1 November 2011 (UTC)

The NIST CODATA site referenced in the article is usually has the best and most up-to-date value. They refine the estimate every few years, maybe that article is using an out-of-date estimate.

Anyway it's hardly worth worrying about a discrepancy in the 8th significant figure. There are only a handful of people in the world who would care what the 8th significant figure of F is, and those people are not looking it up on wikipedia.

By the way, you shouldn't use the term "exact" here -- it's an approximate estimate, not exact. It's very very accurate but it's approximate nonetheless. The uncertainty is indicated in parentheses. :-) --Steve (talk) 22:50, 1 November 2011 (UTC)

comma in a number is nonstandard.

The value is 96 485.3365(21) C/mol, not 96,485.3365(21) C/mol. The comma is confusing and nonstandard. But I don't know how to correct it! Bo Jacoby (talk) 22:12, 10 January 2012 (UTC).

Error in values in beginning section

Both the magnitude of the charge for an electron and Avogadro's constant are missing. — Preceding unsigned comment added by 68.115.36.98 (talk) 01:58, 1 May 2015 (UTC)

Change of name

Knowing that IPs on mobile devices have trouble accessing the page history (but probably the talk page as well) I repeat here my edit summary rolling back the recent edits changing the name to Faraday unit of charge:

Reverted to revision 903402650 by Quondum: We can't have the article using a different name to the page name - too confusing. Change the page name first (ideally at the same time) and discuss first before doing it

Regards, SpinningSpark 16:25, 1 March 2020 (UTC)

Speed of light expressed in dollars

In common units, the speed of light expressed in dollars could be about $ 30 billion (cm/sec) or $186,000 (miles/sec). Mr. Burns is being generous. TomS TDotO (talk) 08:42, 30 December 2020 (UTC)

Minor confusion on 'e' symbols

As an explanation of part of my recent edit: ${\rm {{e}^{-}}}$ (roman type with superscript minus sign) is the symbol for the electron particle, while $e$ (italic, no superscript) is the symbol for the elementary charge or the negative charge on an electron. Indefatigable (talk) 22:29, 8 November 2021 (UTC)

Presentation

Wouldn't it be more natural to present F as the product of the Avogadro number and the elementary charge? I find the current presentation as the ratio between NA and "the number of electrons that a coulomb is the charge of" unnecessarily convoluted, and it makes the connection with e less obvious. 176.159.61.202 (talk) 02:34, 21 February 2022 (UTC)

Edit by User:Indefatigable is dubious !?

The user User:Indefatigable introduced a change aledgedly to make the following example dimensionally correct, however, I think that the edit is wrong and does not consider the conveyed meaning. First, let me copy-paste the current text:

"Since 1 mol electrons is exactly N_A mol = 6.02214076×10²³ electrons, and a coulomb is exactly the (negative) charge of ${\frac {1}{q_{\mathrm {e} }}}={\frac {10^{19}}{1.602176634}}$electrons, the Faraday constant is given by the quotient of these two numbers:

$F={\frac {N_{\mathrm {A} }}{1/q_{\mathrm {e} }}}=96485.3321233100184~\mathrm {C~mol^{-1}}$"

The error is that diving X electrons by Y electrons CANNOT give the units of the Faraday constant which are C per mol. Indeed, dividing X electron by Y electrons gives a pure number X/Y.

So, now let me explain why the original sentence before the introduction of mol was correct:

"Since 1 mol electrons is exactly N_A = 6.02214076×10²³ electrons, and a coulomb is exactly the (negative) charge of ${\frac {1}{q_{\mathrm {e} }}}={\frac {10^{19}}{1.602176634}}$electrons, the Faraday constant is given by the quotient of these two numbers:

$F={\frac {N_{\mathrm {A} }}{1/q_{\mathrm {e} }}}=96485.3321233100184~\mathrm {C~mol^{-1}}$"

Well the actual meaning is that 1 mol of electrons is X electrons per mol, and 1 C of electrons is Y electrons per C, therefore taking the ratio of X electrons per mol / Y electrons per C gives the correct units X/Y C per mol.

Do we need to add "1 mol of electrons is X electrons per mol" and "1 C of electrons is Y electrons per C" ? Well, I do not think so. Once you say that there is 1 mol of electrons, it is grammatically redundant to say "per mol" because it is already specified that we are talking about 1 mol. Nobody says "for 1 hour, I ate 2 cakes per hour".

In summary, I think that the edit by User:Indefatigable is incorrect and does not consider what is the actual meaning of the whole paragraph. One does not need to "fix" the units of "electrons", but needs to consider coming up with the correct units with the displayed formula for F.

Taking into consideration everything that I wrote above, I introduced 3 edits:

• Edit 1: the paragraph was written by someone else by using the verb "is". I have now changed "1 mole is ..." with "1 mole contains ...", because the displayed calculation for F uses electron densities per mol or per coulomb.
• Edit 2: I have further changed "numbers" into "quantities", because numbers are dimensionless, while the quotient uses quantities that have their units, per mol or per C.
• Edit 3: Also 1 coulomb is defined in terms of elementary charges, i.e. the negative of the electron charge, therefore to avoid confusion I have changed "electrons" to "elementary charges".

The revised text has all the units given in brackets and the intended meaning has been made explicit. Danko Georgiev (talk) 19:31, 23 May 2022 (UTC)

I absolutely see your points, but I am uncomfortable with linking expressions that have different dimension with a mathematical equals sign. N_A has dimension N⁻¹, while the right-hand side has dimension 1. Similarly, 1/q_e has dimension T⁻¹I⁻¹, while the right-hand side has dimension 1. I think this lacks scientific rigour. I agree that just adding a unit as I did didn't improve the paragraph: it instead made it harder to understand. I wonder if there is a way to word the paragraph without using an equals sign in those two spots? Now that I have seen the most recent version of the article, I'm OK with how it's worded now. Indefatigable (talk) 20:55, 23 May 2022 (UTC)