Is the Helmholez or Gibbs free energy every used outside of reactions?

In summary, the conversation discusses the usage of Helmholtz & Gibbs free energy outside of chemical reactions. It is mentioned that they may potentially be used in nuclear reactions in a plasma. However, the speaker recalls only using them for chemical reactions in their thermodynamics course. The concept of phase transitions is also discussed, with the conclusion that in a phase transition, the Gibbs function is constant because the heat transferred is equal to the change in enthalpy. This accuracy of this statement is confirmed.
  • #1
swampwiz
571
83
I'm trying to figure out if the Helmholtz & Gibbs free energy are ever used outside of chemical reactions (I suppose they could be used in nuclear reactions in a plasma as well.) It seems to me that they are not, as I can only recall using them for chemical reactions in my thermodynamics course way back when.
 
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  • #2
Phase transitions.
 
  • #3
nasu said:
Phase transitions.

It seems to me that in a phase transition, the Gibbs function is constant. This is so because a phase transition takes place at constant T & P, so the heat transferred Q is equal to the change in H, so

ΔH = Q

ΔS = Q / T = ΔH / T

A = H - T S

ΔA = ΔH - T ΔS = Q - T ( Q / T ) = Q - Q = 0

Is this accurate?
 

Related to Is the Helmholez or Gibbs free energy every used outside of reactions?

1. What is the Helmholez or Gibbs free energy?

The Helmholez or Gibbs free energy is a thermodynamic quantity used to measure the amount of energy available to do work in a system. It takes into account the system's temperature, pressure, and entropy.

2. How is the Helmholez or Gibbs free energy calculated?

The Helmholez or Gibbs free energy is calculated using the formula G = H - TS, where G is the free energy, H is the enthalpy, T is the temperature, and S is the entropy.

3. Is the Helmholez or Gibbs free energy only used in chemical reactions?

No, the Helmholez or Gibbs free energy is used in a wide range of fields, including physics, biology, and engineering. It is a fundamental concept in thermodynamics and is used to understand and predict the behavior of systems.

4. Can the Helmholez or Gibbs free energy be negative?

Yes, the Helmholez or Gibbs free energy can be negative. A negative free energy indicates that the system is in a state of spontaneous change and can release energy to its surroundings.

5. How is the Helmholez or Gibbs free energy used outside of reactions?

The Helmholez or Gibbs free energy is used to determine the stability of a system and to predict the direction of a process. It is also used in the study of phase transitions, biological systems, and other thermodynamic processes.

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