Relation between chemical potential and S,V,T,P

In summary, the conversation discusses the definition of chemical potential and its relationship to the Gibbs potential per particle. It also explains the Gibbs-Duhem equation and its physical significance in studying thermodynamics, particularly in multicomponent systems. Additionally, it highlights the importance of chemical potential in describing multicomponent vapor-liquid equilibrium, multiphase equilibrium, and chemical reaction equilibrium. Finally, it mentions the significance of the derived equation, which only involves intensive parameters.
  • #1
Pushoam
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Homework Statement



upload_2017-12-12_12-2-11.png

Homework Equations

The Attempt at a Solution

Chemical potential is defined as ## \mu = Gibbs potential per particle ##.

So, is the system consists of N particles, ##\mu = \frac { G } {N } ##.

Now, dG = VdP – SdT

## \frac {dG } { N } = \frac { VdP } { N } - \frac { SdT } { N}##

So, ## d{\mu} = -sdT + v dP##.

Hence the correct option is (a).

Is this correct?

I didn't get the physical significane of this question.
How does the knowledge of above eqn help us in our study of thermodynamics?
 

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  • #2
Your answer is correct. This is the Gibbs-Duhem equation which tells us that for a simple system, the intensive parameters (T, P, μ) are not independent. Knowledge of 2 is enough to determine the 3rd up to an integration constant. Have a look at Wiki page too:
https://en.wikipedia.org/wiki/Gibbs–Duhem_equation
 
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  • #3
Pushoam said:
I didn't get the physical significane of this question.
How does the knowledge of above eqn help us in our study of thermodynamics?
For the single component system you are considering, the chemical potential doesn't make much sense. But its value comes into play "big time" when you are considering multicomponent mixtures. It is used in describing multicomponent vapor-liquid equilibrium, multiphase equilibrium, and chemical reaction equilibrium. Be patient, and you will learn about this soon.
 
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  • #4
Thanks for the reply.
The following eqn uses extensive parameters.
Pushoam said:
dG = VdP – SdT
.
We have derived the following eqn from the above eqn. One of the significance of the following eqn is: it consists of only intensive parameters.
Pushoam said:
## d{\mu} = -sdT + v dP##
 

What is chemical potential?

Chemical potential is a measure of the energy that can be obtained or released by a chemical reaction. It is also a measure of the tendency of a substance to change its composition in response to changes in external conditions, such as temperature and pressure.

How is chemical potential related to S,V,T,P?

The chemical potential of a substance is directly related to its entropy (S), volume (V), temperature (T), and pressure (P). It can be expressed mathematically as μ = μ0 + RTln(P/P0) + VΔP + SΔT, where μ0 represents the standard chemical potential at standard conditions, R is the gas constant, P0 is the standard pressure, and ΔP and ΔT represent changes in pressure and temperature, respectively.

What is the significance of chemical potential in thermodynamics?

Chemical potential is a fundamental concept in thermodynamics, as it governs the equilibrium and spontaneity of chemical reactions. It also plays a crucial role in determining the direction and extent of phase transitions, as well as the behavior of solutions and mixtures.

How does chemical potential change with temperature and pressure?

The chemical potential of a substance is directly proportional to temperature and inversely proportional to pressure. As temperature increases, the chemical potential also increases, while increasing pressure decreases the chemical potential. This relationship is governed by the ideal gas law and the van der Waals equation.

Can chemical potential be negative?

Yes, chemical potential can be negative. This occurs when a substance is not in its most stable state and has a tendency to undergo a chemical reaction to reach a more stable state. A negative chemical potential indicates that the substance has a higher potential energy in its current state and can release energy through a chemical reaction.

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