Talk:Thermodynamic activity

message: *Original Lewis' definition is:
::a_i = \frac{f_i}{f^{o}_i} 
so ratio of fugacities. DEfinition is valid for SOLIDS, LIQUIDES and GASES (not only for gases)!!
You can choose denominator (reference fugacity) arbitrarily !!
(only the usage is 101325 as perfect gas for gasses, and fugacity of pure component for solids)
*Lewis definition of fugacity is:
:d\mu_i =  RT  d\ ln(f_i)
*LInk both equetion we get: 
:\mu_i - \mu^{o}_i=  RT \ln {\frac{f_i}{f^{0}_i}} = RT \ln {a_i}  —Preceding unsigned comment added by 212.5.210.202 (talk) 10:34, 25 September 2007 (UTC)
thread_title:  Usable definition, exact as it was defined 

message: Obviously the french and german articals cannot be merged without translation.  If users who speak french or german or preferrably both could judge which is best it could be requested that that article be translated and merged with the english article.  Vuo  Has already suggested that the French article has a lot of good content what are others peoples views and it could then be requested for translation from whichever comes out on top. --Ksbrown 21:03, 22 September 2006 (UTC)
replies: text: I have added it to the french translation board: Wikipedia:Translation_into_English/French#:Activit.C3.A9_chimique Ksbrown 15:39, 23 October 2006 (UTC)
replies: text: The french article was merged with the english article and no original information from the english article was lost.  The translation was done by SamiKaero. -Ksbrown 17:04, 24 October 2006 (UTC)
thread_title:  Merger/Translation 

message: You can find in the article Ideal_solution, that 
If the chemical potential of pure liquid i is denoted \mu_i^*, then the chemical potential of i in an ideal solution is
:\mu_i = \mu_i^* + \Delta \mu_{i,\mathrm{mix}} = \mu_i^* + RT \ln x_i
I guess, that \mu_i^* depends on T and p as well: \mu_i^*(T,p).
Whereas here at Activity (chemistry) one finds
In ideal mixtures we can write the dependency of the chemical potential of a species i on the composition (written as mole fraction x of i) as:
:\mu_i(T,p) = \mu_i^\Theta(T) + R \cdot T \cdot \ln(x_i)
and µi0 is the value of µi under standard conditions.
This means, that \mu_i^\Theta(T) is only function of the temperature and not the pressure, since the pressure is to be taken at p=p^\Theta. But then where has the pressure dependence of \mu_i(T,p) in this second formula disappeared?
--szaboka87.184.93.231 (talk) 17:16, 27 November 2008 (UTC)
thread_title:  <math>\mu_i^*(T,p)</math> vs <math>\mu_i^\Theta(T)</math> 

message: I suspect that in the page the gas constant R is erroneously used instead of the Boltzmann constant kB, but I may be wrong, as it depends on the units of measure. Can someone comment? E prova sta beta (talk) 13:23, 16 September 2009 (UTC)
replies: text: The values R and kB are the same, just multiplied by avagadro's number. R and kB are both the same constant, but the units can be chosen arbitrarily, provided that they can be converted back to either j/(mol.K) or j/(at.K). Engineers and chemists tend to prefer R, and physicists tend to prefer kb. See Boltzmann_constant  User A1 (talk) 02:19, 17 September 2009 (UTC)

text: The title of the article is "Activity (chemistry)" so using the gas constant (R) does seem appropriate. (+)H3N-Protein\Chemist-CO2(-) 14:23, 25 September 2012 (UTC)
thread_title:  Gas constant 

message: Could someone insert some details about choosing  the pure solid as the reference state.--188.26.22.131 (talk) 10:10, 3 July 2013 (UTC)
thread_title:  Standard state for dissolved salt 

message: The article should specify the connection between conductivity (electrolytic) and the thermodynamic activity coeffient of an electrolyte.--188.26.22.131 (talk) 12:59, 9 September 2014 (UTC)
thread_title:  Link to conductivity (electrolytic) 

message: I don't understand why this redirected to the disambiguation page. I've fixed it and tried to write a bit of an article from other sources on the net, but I'm only here because I was looking for information, and I'm not an expert on the topic. Please, chemists, help me!!!
:Redirect doens't work (see my new section)173.189.72.93 (talk) 23:17, 18 November 2014 (UTC)
thread_title: Redirect

message: I was commenting on the article Carbonic Acid and attempted to link to this article and was not able to.
I tried both the following (ignore the "." I use as separator): [.[Thermodynamic activity].] and [.[Thermodynamic_activity].]
Also, the disambiguation page on Activity doesn't have this article, rather the Activity (Chemical) link redirects to here. Could someone who knows what they're doing fix this? Thanks.173.189.72.93 (talk) 23:23, 18 November 2014 (UTC)
thread_title:  Redirect Edit Request 

message: Currently, this page defines relative thermodynamic activity as 
:a_i = e^{\frac{\mu_i - \mu^{\ominus}_i}{RT}}.
"where  is the chemical potential of the species  under the conditions of interest,  is the chemical potential of that species under some defined set of standard conditions."
Given that the universal gas constant  is used, and not Boltzmann's constant , shouldn't  be the molar chemical potential and not the chemical potential?
--Physicsman19 (talk) 17:08, 22 October 2018 (UTC)
replies: text: It is true that molar chemical potential would be more logical, but tradition is just to say chemical potential, as in the IUPAC source and in textbooks. I will add the word (molar) in parentheses, to show that it really is a molar quantity even though the word molar is not usually specified. Dirac66 (talk) 15:09, 24 October 2018 (UTC)
thread_title: Chemical Potential or Molar Chemical Potential?