Entropy and Heat Capacity have the same units. Connection? Redundancy?

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Discussion Overview

The discussion revolves around the relationship between entropy and heat capacity, exploring whether they are fundamentally connected or redundant concepts in thermodynamics. Participants examine the implications of energy transfer between media with different heat capacities and the effects on entropy, as well as the definitions and properties of these quantities.

Discussion Character

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

Main Points Raised

  • Some participants propose that energy tends to flow from media with low heat capacity to those with high heat capacity, potentially affecting the temperature of the transferred energy.
  • Others argue that entropy is not a flow but rather an intensity related to energy transfer, suggesting a conceptual link between entropy and heat capacity.
  • A participant questions the validity of thinking of energy as having a temperature, citing examples of different systems with varying temperatures and their associated energy and entropy levels.
  • Some participants clarify that heat energy transferred during phase changes does not relate to heat capacity, emphasizing that entropy increases in both the system and surroundings during such processes.
  • There is a discussion about the differences between extensive and intensive properties, with a participant asserting that energy, entropy, and temperature are distinct physical quantities.
  • Concerns are raised about the implications of defining energy as having properties like temperature or entropy, with some participants finding such notions nonsensical.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the relationship between entropy and heat capacity, with no consensus reached on whether they are fundamentally connected or distinct concepts. The discussion remains unresolved with ongoing debate about the definitions and implications of these thermodynamic quantities.

Contextual Notes

Participants highlight various assumptions about energy transfer, the definitions of thermodynamic properties, and the implications of phase changes on heat capacity and entropy. There are unresolved questions about the nature of these properties and their interrelations.

  • #31
It should be remembered that temperature is a variable of macroscopic thermodynamics.

As such it performs well in use and is fit for purpose.

When you get to microscopic thermodynamics (which roughly equates to statistical thermodynamics) the concept of temperature becomes less and less useful the smaller you get, as does heat capacity and entropy. This comment also applies to thermodynamics of very sparsely populated systems.

What, for instance, is the temperature, entropy etc of a universe that consists of a single particle?

Associating a temperature with an energy is not possible even in macroscopic thermodynamics. If I move a brick from the floor to the table top in my room there is an energy change but no corresponding temperature change as a result.
 

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