Скачать или смотреть Classical Thermodynamics : Lecture 17 - Legendre transformations and enthalpy

In this lecture I turn to the question - can we change the set of independent variables from S, V, N to some other set and still find a function that contains complete thermodynamic information in a way that U(S,V,N) does? To see how to do this we first introduce the Legendre transformation using a simple example. We describe the geometrical meaning of this transformation and also discuss the condition under which this transformation works. I then apply this transformation to U(S,V,N) to swap out V and replace it with p. This results in the enthalpy. I then show how the enthalpy, expressed as a function of S,p and N contains complete thermodynamic information and follow this up with the example of a monoatomic ideal gas.