Can energy be transferred without doing work?(entropy)

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Discussion Overview

The discussion revolves around the concept of energy transfer without performing work, particularly in the context of entropy. Participants explore how energy can be transferred through various means, including heat, and question the nature of unavailable energy in different processes, such as chemical reactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants assert that energy cannot be transferred without doing work, particularly in relation to entropy.
  • Others argue that energy can be transferred by heat and other means that do not involve work, referencing thermodynamic principles.
  • A participant mentions that heat is defined as the transfer of energy through methods other than work.
  • Mechanical energy transfer is discussed, with an example of a pendulum illustrating that energy can shift between kinetic and potential forms without work being done.
  • Questions are raised about the nature of unavailable energy in chemical reactions and whether all energy can perform work if transformed appropriately.
  • One participant states that the concept of entropy directly relates to the inability of some energy to do work.
  • There is a query regarding the relationship between increasing entropy and the Gibbs free energy, specifically whether an increase in entropy correlates with an increase in available energy for work.

Areas of Agreement / Disagreement

Participants express differing views on whether energy can be transferred without doing work, and there is no consensus on the nature of unavailable energy or its implications in various contexts.

Contextual Notes

Participants reference thermodynamic principles and the Gibbs free energy formula, but there are unresolved questions regarding the definitions and implications of entropy and energy transfer mechanisms.

gladius999
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From my knowledge, I don't see how it is possible for energy to be transferred without doing work as in the case of entropy. What happens to the unavailable energy? how is it transferred in the first place?
 
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gladius999 said:
From my knowledge, I don't see how it is possible for energy to be transferred without doing work as in the case of entropy. What happens to the unavailable energy? how is it transferred in the first place?

Energy can be transferred by heat or many other forms other than work. Take a look at a Thermodynamics textbook and review the section on the "general energy equation".

CS
 
In some sense that is kind of a loose definition of heat. Heat is essentially the transfer of energy through any method besides doing work.
 
Mechanical energy can be transferred from kinetic energy T to potential energy V, and back, like in a pendulum. T + V = constant means no energy loss. No "work" is done in this transfer.

Bob S
 
thanks for answering guys. How come some of the energy transferred is not able to do work? In a chemical reaction where does the unavailable energy come from? I know most energy is transferred as heat. I mean all energy can do work as long as it is transformed right?
 
gladius999 said:
thanks for answering guys. How come some of the energy transferred is not able to do work? In a chemical reaction where does the unavailable energy come from? I know most energy is transferred as heat. I mean all energy can do work as long as it is transformed right?

No. That's exactly what entropy means.
 
gladius999 said:
...How come some of the energy transferred is not able to do work?...

Due to irreversibilities inherent in all systems.

CS
 
I think I'm almost getting to understand this. How come with an increase in entropy, there is an increase in the magnitude of deltaG, the energy available to do work? Should'nt it be a decrease as entropy is unavailable energy? Does the value TS (temperature in kelvin multiplied by entropy) in the gibbs free energy formula equal to the value of energy unable to do work??
 

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