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Physics Start‑class Mid‑importance

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Magnetic field

Is magnetic field also a state function? I feel it should be, but am hesitant to add it since I may be missing some subtlety. Also, the manner in which Markov properties are related to state functions is unclear to me, either from this article or the other. Perhaps this should be clarified or omitted.144.213.253.14 02:21, 31 August 2005 (UTC)[reply]

Political meaning

I think it's worth adding a disambiguation for non-native speakers of the meaning of the term "state function" in contexts such as "Here is a picture of the Vice-President at a state function." Any ideas where such a disambiguation should point? A {{wiktionary}} link would probably be the best solution, if Wiktionary had an entry for state function. --Quuxplusone 16:06, 19 January 2006 (UTC)[reply]

Poorly defined

As I find with most things relating to chemistry, this is a poorly defined term and its vaugeness and ambiguity lead to the inherint wishy-washyness of chemistry. I remember finally understanding what a "state function" was, but I've forgotten my revelation. This page should note some functions that *are not* state functions. I really can't think of anything. Perhaps... is work not a state function.. I'm not sure. Does "state function" mean that only the absolute spatial distance matters, or can the "path" something takes go through other parameters (for example, time, or energy)? Is there anyone knowlegable about this that can unambiguously explain "state function" and what functions its different from. Fresheneesz 10:10, 4 April 2006 (UTC)[reply]

According to Willard Gibbs, W and Q are not functions of the state of the body, where as V, P, T, U, and S are, but instead are determined by the whole series of states through which the body is supposed to pass. I hope this helps?--Sadi Carnot 02:43, 18 July 2006 (UTC)[reply]

Page move proposal

My intuition tells me that this page should ideally be moved to Functions of state. From my experience, this is the most commonly used term. Any comments?--Sadi Carnot 02:43, 18 July 2006 (UTC)[reply]

Done. — Preceding unsigned comment added by Elnsbrook (talk • contribs) 21:00, 17 June 2011 (UTC)[reply]

Chemcial potential

Isn't this quite an important omission form the list of state functions? Initially I thought I must have been mistaken, and that it isn't one, but then it also appears to be in another list in the box in the top right-hand corner — Preceding unsigned comment added by 131.111.185.74 (talk) 11:36, 1 November 2011 (UTC)[reply]

State, not parameter.

The section Functions of state Overview makes frequent reference to functions of state as parameters. They aren't, they are states, they describe the system. Parameters in thermodynamics can be constants such as the Boltzmann constant; the value of the Boltzmann constant (the specific thermal energy of a particle) may be given in terms of Joules/Kelvin; Ev/^oR etc. etc. and it is necessary to ensure that there is consistency with the variables (arguments) used in the equations. But the Boltzmann constant is not a variable, it only relates the variables. --Damorbel (talk) 08:59, 17 January 2013 (UTC)[reply]

No. State variables are not "states". A "state variable" is something like entropy, pressure, volume; whereas a (macroscopic or microscopic) "state" of the system is something that corresponds to a full macroscopic or microscopic description of the system, such that different descriptions correspond to different states, and vice-versa. Jheald (talk) 21:19, 17 January 2013 (UTC)[reply]

Opening statement

The opening statement contains the assertion:-

'A state function describes the equilibrium state of a system.'

This is far from correct. The system does not have to "be in equilibrium" to have properties such as, internal energy, enthalpy, and entropy, as the article says.

This may appear trivial to the uninitiated. But, for example, a system only achieves maximum entropy when in equilibrium. However it still has a (lower) entropy before achieving equilibrium. --Damorbel (talk) 10:11, 17 January 2013 (UTC)[reply]

The point of a state function is that it is determined uniquely by the macroscopic variables.

But it is only the equilibrium state that that is true for. There may be many non-equilibrium states with the given values of volume and pressure, and it is not clear that temperature has a well-defined meaning at all for a non-equilibrium state. Jheald (talk) 13:04, 17 January 2013 (UTC)[reply]

...determined uniquely by the macroscopic variables. Only true for extensive variables such as energy and entropy. Not remotely true for intensive variables unless the system is in equilibrium. Even entropy can only be determined easily for systems with carefully identified (dis)equilibrium e.g. System 1 at T₁ and System 2 at T₂. These conditions normally occur only in the heads of university lecturers and their textbooks! --Damorbel (talk) 13:35, 17 January 2013 (UTC)[reply]

@@ Line 26: / Line 26: @@
 The section [[Functions_of_state#Overview|Functions of state Overview]] makes frequent reference to functions of state as parameters. They aren't, they are ''states'', they describe the system.
 Parameters in thermodynamics can be constants such as the [[Boltzmann constant]]; the value of the Boltzmann constant (the specific thermal energy of a particle) may be given in terms of Joules/Kelvin; Ev/<sup>o</sup>R etc. etc. and it is necessary to ensure that there is consistency with the variables (arguments) used in the equations. But the Boltzmann constant is not a variable, it only relates the variables. --[[User:Damorbel|Damorbel]] ([[User talk:Damorbel|talk]]) 08:59, 17 January 2013 (UTC)
+:No. State variables are not "states".  A "state variable" is something like entropy, pressure, volume; whereas a (macroscopic or microscopic) "state" of the system is something that corresponds to a ''full'' macroscopic or microscopic description of the system, such that different descriptions correspond to different states, and vice-versa. [[User:Jheald|Jheald]] ([[User talk:Jheald|talk]]) 21:19, 17 January 2013 (UTC)
 == Opening statement ==