Something I don't understand about work, heat, and entropy.

In summary, the conversation discusses the concept of maximum entropy and its implications on the ability to extract heat and perform work in a system. While other sources of work exist, maximum entropy typically refers to macroscopic work and the violation of a temperature gradient can cause issues with the second law of thermodynamics.
  • #1
zeromodz
246
0
I've been doing a lot of research on how the sum of a systems change and the environments change from point a to be always increases in entropy for irreversible processes. My question really has to do with heat and work during maximum entropy.

Once a system reaches maximum entropy where the temperature is completely uniform. I understand that no heat can be extracted from the system, but why does that necessarily mean there will be no more work? I know that there are other ways that can perform work like gravity, atomic forces, electric potential, and so forth. Heat transfer isn't the only way to extract work right? Why do all these sources I read from say that after a system reaches maximum thermodynamic entropy, no more work is performed?
 
Science news on Phys.org
  • #2
Maximum entropy implies that a system exhibits not only uniform temperature, but also uniform pressure, electrical charge, magnetic field, stress, surface tension, and so on.
 
  • #3
It refers to macroscopic work. The Carnot cycle efficiency depends on a temperature gradient. If this is violated, then there should be trouble for the second law of thermodynamics, since the Carnot cycle run backwards is used to prove the equivalence of the Kelvin and Clausius statements.
 

Related to Something I don't understand about work, heat, and entropy.

1. What is the difference between work and heat in thermodynamics?

Work and heat are both forms of energy transfer in thermodynamics, but they differ in their mechanisms. Work involves the transfer of energy by means of a force acting through a distance, while heat involves the transfer of energy due to a temperature difference.

2. How does the concept of entropy relate to work and heat?

Entropy is a measure of the amount of disorder or randomness in a system. In thermodynamics, work and heat can both contribute to changes in entropy. Work can increase or decrease the entropy of a system, while heat transfer always increases the entropy of a system.

3. What is the second law of thermodynamics and how does it relate to work, heat, and entropy?

The second law of thermodynamics states that the total entropy of an isolated system will never decrease over time. This means that in any energy transfer, the total entropy of the system and its surroundings will always increase. In the case of work and heat, both forms of energy transfer will always result in an increase in entropy.

4. How does the concept of reversibility apply to work, heat, and entropy?

In thermodynamics, a reversible process is one in which the system and its surroundings can be returned to their original states after the process is reversed. In the case of work and heat, reversible processes have no effect on entropy since the system and surroundings are returned to their original states. However, irreversible processes, such as friction, will always result in an increase in entropy.

5. Can work be converted into heat, or vice versa?

Yes, work and heat are interchangeable in certain situations. For example, in a heat engine, work is converted into heat to do useful work. However, due to the second law of thermodynamics, some of the work will always be lost as heat in the process, resulting in an overall increase in entropy. Similarly, heat can also be converted into work in a heat pump or refrigerator, but again, some energy will be lost as heat and entropy will increase.

Similar threads

Replies
15
Views
1K
Replies
13
Views
2K
Replies
58
Views
4K
Replies
12
Views
2K
  • Thermodynamics
Replies
2
Views
845
Replies
17
Views
2K
Replies
22
Views
2K
  • Thermodynamics
Replies
3
Views
842
Replies
3
Views
1K
Back
Top