Editing Chemical Potential (section)

== Definition ==
In thermodynamics, the chemical potential ''μ'' of a component in a system is defined as the partial derivative of the system's Gibbs free energy ''G'' with respect to the number of moles ''nᵢ'' of the component, at constant temperature ''T'' and pressure ''P'':

 :μᵢ = (∂G/∂nᵢ) at constant T, P, and nⱼ (j ≠ i)

Alternatively, depending on the thermodynamic potential being used, chemical potential can also be defined using internal energy ''U'', enthalpy ''H'', or Helmholtz free energy ''A''. For example, in terms of internal energy:

    μᵢ = (∂U/∂nᵢ) at constant S, V, and nⱼ (j ≠ i)

Here, 
* ''G'' is the Gibbs free energy,
* ''U'' is the internal energy,
* ''S'' is the entropy,
* ''V'' is the volume,
* ''nᵢ'' is the number of moles of component ''i'',
* The subscript ''j ≠ i'' indicates that the number of moles of all other species is held constant.