Talk:Thermodynamic equilibrium

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1.What the formula for specific heat capacity????

see Heat capacity, Specific heat capacity

2.What the formula for specific latent heat of vaporization and specific latent heat of fusion?

see Latent heat, Heat of fusion, Heat of vaporization.

Please show some examples that can prove the formula are correct.

Please help us improve articles. If this article Thermodynamic equilibrium would be improved by the above links, please add those links to the article. --DavidCary 13:11, 23 September 2005 (UTC)

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'Local t. e.' Anybody got a reference for that? It's not what my understanding is.GangofOne 06:28, 15 August 2005 (UTC)

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The first paragraph is general but good. I have a problem with LTE, namely the field to which these considerations apply need be mentioned (heat transfer?). Local thermodynamic equilibrium can mean many other tings, for instance it is an hypothesis on which calculations of collective diffusive processes are often based (not only radiation heat), and the basis for the Onsager approachuser:ThorinMuglindir

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The definition of TE should include the word "isolated" somewhere - otherwise we could be talking about a non-equilibrium stationary state, for example a material with a constant flow of heat through it. The zeroth law then needs to say that the systems in equilibrium need to be in contact with each other, but otherwise isolated. The LTE is too specific - it should say that parts of the system are approximately equilibrium states, but not in equilibrium with each other, for example if the temperature varies with position. Carl Dettmann, Bristol 24 October 2005.

Global thermodynamic equilibrium means that the values of intensive parameters are homogeneous throughout the whole system Temperature certainly and pressure maybe, but density by no means (e.g. water at the triple point). --Art Carlson 17:23, 25 October 2005 (UTC)

Art, you are certainly right, that statement is too far-encompassing. Density doesn't work because it is not a quantity linked to the exchange of some extensive quantity (like pressure is linked to the exchange of volume, and temperature is linked to the exchange of heat). Otherwise on another notice sometimes the intensive parameter that controls equilibrium is not always something simple as (just) P. For example, in the presence of a gravity field, equilibrium is reached not when P is constant, but rather when P − ρgz is constant over the system. It seems the text needs to be more careful, though I need a bit of thinking in order to explain these subtleties as simply as possible. The rewriting from what I left is great.ThorinMuglindir 21:17, 25 October 2005 (UTC)

OK I made a more careful rewriting of that part.ThorinMuglindir 22:57, 29 October 2005 (UTC)

On a similar notice I reworded slightly the part about the glass of water at the end. An out-of-equilibrium state can be maintained in a system, not only "artificially maintained" as I had written. For example, the sun maintains a certain amount of non-equilibrieum on the surface of earth, but this is not "artifical."ThorinMuglindir 21:28, 30 October 2005 (UTC)

Two points:

• Density gradients are linked to the exchange of mass, through the process of diffusion

• diffusion of molecules will sometimes happen according to the gradient of density (like within a gas, if gravity is negligible), but not always (like at a liquid vapor interface). I believe that most generally, diffusion of a certain species will happen according to the gradient of chemical potential of that species: that's μ in thermodynamics equations and μ_j in statistical mechanics (grand-canonical ensemble).

• What is the equilibrium nature of water at the triple point, in the absence of gravity and boundaries? Would there be a tendency as time goes by to form large scale density variations, like water/ice planets, or would it be a big cloud of small ice crystals and water droplets? If so, how small? PAR 22:05, 30 October 2005 (UTC)

• If the system is not submitted to external gravity, but gravity between components of the system would remain, there would be a tendancy to form ice and water planets (or planets made of both more probably), though that would be only for very large systems. If gravity is totally suppressed, or for a smaller system, capillarity would prevent water drops from divinding when they are below a certain size. Sometimes two water drop would collide each other and merge. Big droplets would have a tendancy to divide, but would this process eventually eliminate all water masses above a certain size before they have time to form by random merging? I can't answer to this last question.ThorinMuglindir 23:58, 30 October 2005 (UTC)

That makes sense, except the part about large droplets having a tendency to divide. What's the force causing the division, just the random accumulation of angular momentum? PAR 02:47, 31 October 2005 (UTC)

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Shouldn't the relation of thermodynamic equilibrium to entropy (specifically, the fact that entropy is maximized at equilibrium) be mentioned in here somewhere? I'm not knowledgeable enough about the technical details to add it myself, but I thought it was pretty important. Hypnosifl 21:50, 19 October 2006 (UTC)

[edit] Steady state versus uniform conditions

It would seem the article needs to make a clearer distinction between the concepts of a "uniform" medium versus a system in steady state, the latter allowing spatial but not temporal dis-uniformity. I can take a stab at some of this in the thermal context. Rnestle 18:31, 22 February 2007 (UTC)

There's another state - equilibrium, which may not be uniform but will be steady state. This article should confine itself to the equilibrium state, with mention of other possibilities which should be developed in their own article. PAR 20:25, 22 February 2007 (UTC)

As far as other articles, shouldn't we have an article called Thermal equilibrium? presently that link just takes one to the present article. Rnestle 21:40, 22 February 2007 (UTC)