Overview: Classical thermodynamics

In this chapter you will learn about classical thermodynamics. You will learn about the extensive and intensive variables that we use to characterise the state of the system in this theory and about how can understand the ways these state functions change by using relatively simple partial differential equations. You will then learn about the laws of thermodynamics and how we can use these laws to construct thermodynamic potentials, Maxwell relations and inequalities involving response functions. These last inequalities are particularly important as these are the concrete predictions that allow us to test whether or not this body of theory correctly describes reality.


  • You should be able to give a list of thermodynamic variables and state whether or not these variables are intensive or extensive by describing how such variables behave in a system at equilibrium.
  • You should be able to use Gibbs Phase Rule to determine the number of independent thermodynamic variables for a system in equilibrium based on a description of that system.
  • You should be able to give definitions for commonly used terms in thermodynamics such as adiabatic, isochoric, isobaric, isothermal, open, closed, isolated and diathermal.
  • You should be able to state the first and second laws of thermodynamics and then use these results and the definitions of the various thermodynamic potentials to derive Maxwell relations and inequalities involving the various reponse functions
  • You should be able to discuss how thermodynamic variables, response functions and thermodynamic potentials behave when a system undergoes 1st order phase transition and how this differs from the behavior of these quantities when the system undergoes a continuous phase transition.

Contact Details

School of Mathematics and Physics,
Queen's University Belfast,

Email: g.tribello@qub.ac.uk
Website: mywebsite