In thermodynamics, Bridgman's thermodynamic equations are a basic set of thermodynamic equations, derived using a method of generating a large number of thermodynamic identities involving a number of thermodynamic quantities. The equations are named after the American physicist Percy Williams Bridgman. (See also the exact differential article for general differential relationships). In thermodynamics, there are a large number of equations relating the various thermodynamic quantities. ... The laws of thermodynamics, in principle, describe the specifics for the transport of heat and work in thermodynamic processes. ... Thermodynamic potentials Maxwell relations Bridgmans equations Exact differential (edit) In thermodynamics, the internal energy of a system is expressed in terms of pairs of conjugate variables such as pressure/volume or temperature/entropy. ... In thermodynamics, thermodynamic potentials are parameters associated with a thermodynamic system and have the dimensions of energy. ... The thermodynamic properties of materials are intensive thermodynamic parameters which are specific to a given material. ... Maxwells relations are a set of equations in thermodynamics which are derivable from the definitions of the thermodynamic potentials. ... In mathematics, a differential dQ is said to be exact, as contrasted with an inexact differential, if the function Q exists. ... For more elaboration on these equations see: thermodynamic equations. ... Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dynamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... Percy Williams Bridgman (April 21, 1882–August 20, 1961) was an American physicist who won the 1946 Nobel Prize in Physics for his work on the physics of high pressures. ... In mathematics, a differential dQ is said to be exact, as contrasted with an inexact differential, if the function Q exists. ...

The extensive variables of the system are fundamental. Only the entropy S , the volume V  and the four most common thermodynamic potentials will be considered. The four most common thermodynamic potentials are: For other uses, see: information entropy (in information theory) and entropy (disambiguation). ... For other uses, see Volume (disambiguation). ...

Internal energy	U
Enthalpy	H
Helmholtz free energy	A
Gibbs free energy	G

The first derivatives of the internal energy with respect to its (extensive) natural variables S  and V  yields the intensive parameters of the system - The pressure P  and the temperature T . For a simple system in which the particle numbers are constant, the second derivatives of the thermodynamic potentials can all be expressed in terms of only three material properties In thermodynamics, the internal energy of a thermodynamic system, or a body with well-defined boundaries, denoted by U, or sometimes E, is the total of the kinetic energy due to the motion of molecules (translational, rotational, vibrational) and the potential energy associated with the vibrational and electric energy of... t In thermodynamics and molecular chemistry, the enthalpy or heat content (denoted as H or ΔH, or rarely as χ) is a quotient or description of thermodynamic potential of a system, which can be used to calculate the useful work obtainable from a closed thermodynamic system under constant pressure. ... In thermodynamics, the Helmholtz free energy is a thermodynamic potential which measures the “useful” work obtainable from a closed thermodynamic system at a constant temperature. ... In thermodynamics, the Gibbs free energy is a thermodynamic potential which measures the useful work obtainable from a closed thermodynamic system at a constant temperature and pressure. ... This article is about pressure in the physical sciences. ... For other uses, see Temperature (disambiguation). ... The particle number, N, is the number of so called elementary particles (or elementary constituents) in a thermodynamical system. ... The thermodynamic properties of materials are intensive thermodynamic parameters which are specific to a given material. ...

heat capacity (constant pressure)	CP
Coefficient of thermal expansion	α
Isothermal compressibility	βT

Bridgman's equations are a series of relationships between all of the above quantities. To meet Wikipedias quality standards, this article or section may require cleanup. ... In physics, thermal expansion is the tendency of matter to change in volume in response to a change in temperature. ... Fluid Dynamics Compressibility (physics) is a measure of the relative volume change of fluid or solid as a response to a pressure (or mean stress) change: . For a gas the magnitude of the compressibility depends strongly on whether the process is adiabatic or isothermal, while this difference is small in...

Introduction

Many thermodynamic equations are expressed in terms of partial derivatives. For example, the expression for the heat capacity at constant pressure is:

which is the partial derivative of the enthalpy with respect to temperature while holding pressure constant. We may write this equation as:

This method of rewriting the partial derivative was described by Bridgman (and also Lewis & Randall), and allows the use of the following collection of expressions to express many thermodynamic equations. For example from the equations below we have:

and

Dividing, we recover the proper expression for C_P.

The following summary restates various partial terms in terms of the thermodyamic potentials, the state parameters S, T, P, V, and the following three material properties which are easily measured experimentally. The thermodynamic properties of materials are intensive thermodynamic parameters which are specific to a given material. ...

Bridgman's thermodynamic equations

Note that Lewis and Randall use F and E for the Gibbs energy and internal energy, respectively, rather than G and U which are used in this article.

See also

• Table of thermodynamic equations

For more elaboration on these equations see: thermodynamic equations. ...

References

• Bridgman, P.W. (1914). "A Complete Collection of Thermodynamic Formulas". Phys. Rev. 3 (273).
• Lewis, G.N.; Randall, M. (1961). Thermodynamics, 2nd Edition, New York: McGraw-Hill Book Company.