Problems and Solutions on Thermodynamics and Statistical Mechanics

Ideal systems in classical thermodynamics

“…For τ -L systems, the generalized parameters are A = −τ and a = L, so that equation (10) requires that L 0 is independent of temperature if Joule's law is to be obeyed. This fact is frequently ignored in the literature [5][6][7]9], though some authors have noted it previously [8,10,15]. Note that if L 0 does not depend on T for an ideal elastomer, the linear expansion coefficient of an unstretched elastomer…”

“…Besides the classical ideal gas, the ideal paramagnetic substance [1][2][3][4] and the ideal rubber-like elastic material (or ideal elastomer) [5][6][7][8][9][10][11][12][13][14][15] are two widely used examples. The classical ideal gas is characterized by the fulfilment of two conditions, e.g.…”

“…For the rubber-like elastic material and the ideal paramagnetic substance, the attribute 'ideal' is often given to systems whose internal energy is a function exclusively of temperature [1,2,4,[10][11][12][13][14][15]; however, some authors do not mention this requirement explicitly [3]. Finally, there are other texts that use the attribute 'ideal' for systems which do not obey Joule's law [5][6][7]9]. In this context, the question of what conditions a thermodynamic system should meet to be considered 'ideal' arises naturally.…”