Joule's Expansion & Entropy Production

In summary, the conversation discusses the concept of free expansion of gases under adiabatic conditions and constant temperature, which results in no work being done by the gas. However, there is an increase in entropy, which raises the question of where the unavailable energy associated with entropy comes from. It is clarified that this process cannot be isothermal and requires heat energy to maintain the temperature.
  • #1
hyperickz
4
0
We all know that in free expansion of gases under adiabatic condition and keeping the temperture constant ,we get that no work is done by the gas.Moreover since del(Q)=0, del(U)=0 according to first law of thermodynamics.But we get a increase of entropy by an amount Rln2.Now the question is that from where does the unavailable energy associated with entropy i.e. Tdel(S)=RTln 2 comes from ?
 
Science news on Phys.org
  • #2
hyperickz said:
We all know that in free expansion of gases under adiabatic condition and keeping the temperture constant
Is this possible?
 
  • #4
joule thompson effect does not take place isothermally.
 
  • #5
Its not joule thomson effect.Its free expansion of ideal gas during which temperature remains same due to perfect thermal isolation
 
  • #6
thermal isolation provides only adiabatic conditions not isothermal, for the gas to expand and still maintain its temperature you'll have to supply heat energy.
bottom line, the process you are referring to cannot be isothermal.
 

1. What is Joule's expansion?

Joule's expansion refers to the process in thermodynamics where a gas expands into a vacuum, causing a decrease in temperature and an increase in volume.

2. How does Joule's expansion relate to entropy production?

Joule's expansion is a reversible process that results in an increase in entropy, which is a measure of the disorder or randomness of a system. This increase in entropy is known as entropy production.

3. What is the significance of entropy production in thermodynamics?

Entropy production is a fundamental concept in thermodynamics as it represents the irreversible processes that occur in a system. It is also a measure of the amount of energy that is converted into heat and cannot be used to do work.

4. How is Joule's expansion and entropy production related to the second law of thermodynamics?

Joule's expansion and entropy production are both examples of processes that align with the second law of thermodynamics, which states that the total entropy of a closed system will always increase over time.

5. Can Joule's expansion and entropy production be applied to real-world situations?

Yes, Joule's expansion and entropy production can be observed in various real-world situations, such as the expansion of a gas in an engine or the diffusion of gases in a room. These processes are essential in understanding energy transfer and conversion in everyday life.

Similar threads

Replies
4
Views
1K
Replies
22
Views
2K
Replies
13
Views
1K
Replies
15
Views
1K
Replies
21
Views
3K
Replies
2
Views
816
Replies
9
Views
1K
  • Thermodynamics
Replies
5
Views
920
  • Thermodynamics
Replies
1
Views
1K
  • Thermodynamics
Replies
1
Views
1K
Back
Top