What does the symbol F represent in Bridgman's thermodynamic equations?

In Bridgman's thermodynamic equations, the symbol F specifically represents Helmholtz free energy. Helmholtz free energy is a thermodynamic potential that measures the useful work obtainable from a closed thermodynamic system at constant temperature and volume. It is defined mathematically as the difference between the internal energy of the system and the product of its temperature and entropy. This potential is particularly useful in situations where the volume and temperature are held constant, providing insight into the system's ability to perform work under these constraints.

This concept contrasts with the other forms of thermodynamic potentials, such as Gibbs free energy, which is more relevant at constant temperature and pressure, internal energy, which pertains to the total energy of the system, and enthalpy, which is the total heat content of a system. Each of these potentials serves distinct roles in thermodynamic analyses, emphasizing the importance of understanding the context and conditions under which the equations apply.