In regards to Asshole (disambiguation) page

Hello! I've check the page and there was some pretty moronic vandalism there too. However, If I make a request for a semi-protection, I doubt that they will protect it, because they useally protect it when after consective and numerous bouts of vandalism, just like the parent Asshole article. The one you were taking only had 3 cases of vandal since the month started. In my past protection requests such as Bill Clinton and North Korea, the vandalism was useally one per hour or even more. So in my standards, I would not ask the administrator for page protection for this one, although if you feel that it should need a semi-protection you can go to Wikipedia:Requests for page protection. Have a great day! JForget 17:09, 14 October 2006 (UTC)[reply]

re fr:Activité chimique

I think that its the scientific jargon that is very much in need in the english article. It appears to my untrained language eye (for french anyway) that the french article describes the mathematical formulae very well as one person said it had good content and it appears that the text is well organised. The English artical has the non mathematical description but if you could translate the most of the french article (from Le potentiel chimique µ_i) I would happily reorganise the english article because it needs that doing anyway. If there are any jargon terms you can't translate put the french and enlgish guess together and I will easiliy be able to put the correct english equivalent.

Basically the people that wrote the french article appear to have given a very good mathematical description which the english artical is lacking. If you are happy to translate it let me know when its finished and I will check and/or reorganise it. Thank you Ksbrown 09:23, 24 October 2006 (UTC)[reply]

No problem. Thank you/merci. Ksbrown 13:09, 24 October 2006 (UTC)[reply]

Thank you for doing that, it is very helpful. In case it is helpful to you, I have put the copy of the translation that I proof read below so you can see what I changed before I merge it with the rest of the article. Thanks again, Ksbrown 16:19, 24 October 2006 (UTC)[reply]

Proof read translation

The chemical activity of a species is the influence of the amount of substance of a species on the Helmholtz free energy of a system.

The chemical potential µ_i of a species i is the partial derivative of the Gibbs free energy of the system compared to the amount of substance n_i (number of moles):

\mu _{i}={\frac {\partial G}{\partial n_{i}}}

This chemical potential depends on the temperature T, pressure p and the activity a_i according to the formula :

\mu _{i}(T,p)=\mu _{i}^{0}(T)+R\cdot T\cdot \ln(a_{i})

where R is the Ideal Gas Constant and µ_i⁰ is the value of µ_i under standard conditions.

For a gaseuos mixture

The activity is of the form:

a_{i}=\gamma _{i}\cdot x_{i}\cdot {\frac {p}{p_{0}}}={\frac {f_{i}}{p_{0}}}

where $\gamma _{i}$ is the dimensionless fugacity coefficient (fugacity) of the species i, x_i the mole fraction of the species in the gaseous mixture and p the pressure expressed in bar.

The quantity $f_{i}$ has the dimension of pressure and is fugacity of the gas: for a pure Ideal gas, the fugacity coefficient is equal to one.

The value p₀ is the standard atmospheric pressure. It is equal to 1 bar and is present to cancel the dimensions of the formula. Thus:

\mu _{i}(T,p)=\mu _{i}^{0}(T)+R\cdot T\cdot \ln(\gamma _{i}\cdot x_{i}\cdot {\frac {p}{p_{0}}})

For compound in a liquid solution

The activity is of the form:

a_{i}=\gamma _{i}{\frac {C_{i}}{C_{0}}}

Where $\gamma _{i}$ is the coefficient of activity of the species i, C_i is concentration in solution expressed in mol.l^-1. The C₀ term is equal to 1 mol·l^-1 and is present to cancel the dimensions of the formula. Therefore:

\mu _{i}(T,p)=\mu _{i}^{0}(T)+R\cdot T\cdot \ln(\gamma _{i}\cdot {\frac {C_{i}}{C_{0}}})

It should be noted that in a liquid solution the activity coefficient of a given ion (e.g. Ca²⁺) isn't measurable because it is experimentaly impossible to independantly measure the electrochemical potential of an ion in solution. Therefore one introduces the notion of 'average activity coefficient'.

Simplifications

The above formulae can be simplified by considerating that:

For a chemical solution:
- the solvent has an activity of unity
- At a low concentration, the activity of a solute can be approximated to the ratio of its concentration over the standard concentration:
  $a_{i}={\frac {C_{i}}{C_{0}}}$
  Therefore, it is approximately equal to its concentration in mol·l^-1.
For a mix of gas at low pressure, the activity is equal to the ratio of the partial pressure of the gas over the standard pressure:
$a_{i}={\frac {p_{i}}{p_{0}}}$
Therefore, it is equal to the partial pressure in bars (compared to a standard pressure of 1 bar).
For a solid body, a uniform, single species solid has an activity of unity.

The chemical activities should be used to define the equilibrium constant but in practice often concentrations are used.