This page develops the Helmholtz free energy from the point of view of thermal and statistical physics. For applications to chemistry, see work content.
The Helmholtz free energy is a state function of a system defined as
- F = U - TS
where F is the Helmholtz free energy in joules,
U is the energy of the system in joules,
T is the temperature in kelvin,
and S is the entropy in joules per kelvin.
Note: in some literature, this quantity is referred to as A.