Why are only five out of eight possible thermodynamic potentials important?

Click For Summary
SUMMARY

The discussion centers on the significance of five key thermodynamic potentials: Entropy, Helmholtz free energy, Enthalpy, Gibbs free energy, and Grand potential, derived from the fundamental equation dE=tdS-PdV+\mu dN. The other three potentials are less relevant due to their association with less common conditions, such as constant entropy or chemical potential, which are not typically encountered in standard thermodynamic applications. Notably, one potential, represented as E-TS+PV-\muN, is identically zero, further diminishing its practical importance.

PREREQUISITES
  • Understanding of thermodynamic potentials and their derivation
  • Familiarity with the fundamental thermodynamic equation dE=tdS-PdV+\mu dN
  • Knowledge of conditions such as constant temperature and constant particle number
  • Basic principles of statistical mechanics
NEXT STEPS
  • Read "Eight physical systems of thermodynamics, statistical mechanics, and computer simulations" by Graben and Ray
  • Explore the implications of constant entropy and chemical potential in thermodynamics
  • Investigate the applications of the less common thermodynamic potentials
  • Study the relationship between thermodynamic potentials and statistical mechanics
USEFUL FOR

Students and professionals in physics, particularly those specializing in thermodynamics and statistical mechanics, as well as researchers interested in the applications of thermodynamic potentials.

ati
Messages
1
Reaction score
0
Starting from the equation

dE=tdS-PdV+[tex]\mu[/tex] dN

It is straightforward to derive all 8 possible thermodynamic potentials. My question is the following: Why are the only important potentials

Entropy
Helmholtz free energy
Enthalpy
Gibbs free energy
Grand potential ?

Why aren't the other three as relevant as these?

Thanks for your help
-Ati
 
Physics news on Phys.org
Hi ati, welcome to PF. Systems with constant entropy or constant chemical potential are somewhat less familiar to us than systems with constant temperature or constant particle number. Potentials are still defined and used for the more exotic systems even though they aren't mentioned in most thermodynamics texts. Also, note that one of the potentials (E-TS+PV-[itex]\mu[/itex]N) is identically zero!

You may be interested in reading Graben and Ray's "Eight physical systems of thermodynamics, statistical mechanics, and computer simulations" Molecular Physics 80(5) (1993).
 
Last edited:

Similar threads

Undergrad Minimization of the Gibbs energy when number of molecules varies
  • · Replies 16 ·
Replies
16
Views
3K
Chemistry How to derive 2nd law extremum principles for U, A, G, and H?
  • · Replies 1 ·
Replies
1
Views
3K
What is the significance of thermodynamic potentials?
  • · Replies 1 ·
Replies
1
Views
2K
Chemistry Show that book levitation by absorption of heat violates 2nd law
  • · Replies 13 ·
Replies
13
Views
3K
Thermodynamics: determining potentials
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Change of Variables in Thermodynamics
  • · Replies 4 ·
Replies
4
Views
3K
Graduate Partial derivatives of thermodynamic state functions
  • · Replies 1 ·
Replies
1
Views
2K
Which is not a thermodynamical potential
  • · Replies 4 ·
Replies
4
Views
2K
Graduate Thermodynamic equation of differentials (and how to work with them)
  • · Replies 1 ·
Replies
1
Views
1K
Thermodynamics: Irreversible process.
  • · Replies 6 ·
Replies
6
Views
6K