For a chemical system, molar free energy is known as Chemical Potential.
A chemical substance that is free to move from one place to another place, will move spontaneously from a state of higher chemical potential to a state of lower chemical potential.
In the position of equilibrium, the chemical potential is constant through the entire system.
Let us consider a general heterogeneous system consisting of an independent components in several coexisting phases.
To start with, it is convenient to describe a given phase by its chemical composition, which is specified by the no. of mole 'Ni' of each species i, its volume V and its entropy 'S'.
If we consider internal energy (U)
'μi' is chemical potential of component 'i' in given phase.
We can also consider chemical potential 'μ' in terms of Helmoltz free energy 'F'.
The chemical potentials are thus the rate of change of free energy per mole, at constant volume and temperature.
μ can also be expressed as
A System in external field will be in equilibrium if the temperature and chemical potential of each component of the system is constant through out, i.e.
A chemical substance that is free to move from one place to another place, will move spontaneously from a state of higher chemical potential to a state of lower chemical potential.
In the position of equilibrium, the chemical potential is constant through the entire system.
Let us consider a general heterogeneous system consisting of an independent components in several coexisting phases.
To start with, it is convenient to describe a given phase by its chemical composition, which is specified by the no. of mole 'Ni' of each species i, its volume V and its entropy 'S'.
If we consider internal energy (U)
U=U(S,V,N₁,N₂,.....Nᵢ,.....Nn)
μi=❴∂U/∂Nᵢ❵S,V,Nj ; j= except 'i'
'μi' is chemical potential of component 'i' in given phase.
dU=TdS-PdV+Σμᵢi.dNᵢ for i=1...n
We can also consider chemical potential 'μ' in terms of Helmoltz free energy 'F'.
F = F(T,V,N₁,N₂......Nn)
μ1=❴∂F/∂N1❵T,V,N₂,....
μ2=❴∂F/∂N2❵T,V,N₁,N₃,....
The chemical potentials are thus the rate of change of free energy per mole, at constant volume and temperature.
μ can also be expressed as
μi=❴∂G/∂Nᵢ❵T,P,Nj
A System in external field will be in equilibrium if the temperature and chemical potential of each component of the system is constant through out, i.e.
dT₁=0 and dμᵢ=0
No comments:
Post a Comment