Callen's book has the significant merit of presenting a reasonable account of an axiomatic approach to Equilibrium Thermodynamics, following the path laid out by Tisza (Tisza, L. (1961). The ...

Callen's postulate mixing definition of equilibrium states with internal energy seems quite strange to me.An equilibrium state is defined by the presence of thermodynamic equilibrium: constancy of ...

A satellite will tend to become tidally locked, so that the same side always faces the primary. If the object has a long axis, tidal forces will tend to align the long axis on the line between the ...

Accepted

I'll try to complement the already excellent answer by @naturallyInconsistent with a more comprehensive discussion from the mathematical point of view, and a purely thermodynamic argument, from the ...

The rigorous mathematics of classical thermodynamics only works in the thermodynamic limit, which, amongst other requirements, require that $N\to\infty$This is also the limit in which all the finite ...

Every branch and aspect of science starts out by making approximations and simplifications in order to make progress. Elementary particle physics, with things like the fine structure constant and $g-2$...

Entropy is only postulated to exist for equilibrium states. In a non-equilibrium state, there is no entropy to speak of.There are idealized processes called quasi-static processes. In such processes, ...

The discussion was about a counter-example to the claim that $dQ=TdS$for any arbitrary, quasi-static process.While I don’t wish to enter into a debate with the “knowledgeable users” you’ve been ...

Accepted

...And since subsystem (2) is obviously not in equilibrium, neither is subsystem (1), as shown by the thought experiment earlier. So how do we motivate the use of equations such as eq. (1) and the ...

Thermodynamic equilibrium takes on an axiomatic status in thermodynamics. As such it is something that is defined and treated as an unchallenged. This makes sense when we consider that all physical ...

In statistical mechanics, the pressure $p$ is calculated from the Helmholtz free energy $F$:$$p = -\left( \frac{\partial F}{\partial V} \right)_{T,N},$$and the free energy $F$ is expressed in ...