What is the Joule Thomson Effect and why does it matter for real gases?

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    Joule Thomson
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Discussion Overview

The discussion centers on the Joule-Thomson effect, particularly its implications for real gases during adiabatic expansion. Participants explore the differences between ideal and real gases in this context and the historical significance of the effect.

Discussion Character

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

Main Points Raised

  • One participant states that the Joule-Thomson effect occurs when a real gas expands adiabatically, suggesting it behaves similarly to an ideal gas with some minor differences.
  • Another participant questions the initial understanding, indicating that the discussion may conflate isentropic and general adiabatic expansion, noting that real gases can experience an increase in temperature during expansion.
  • A different participant emphasizes that the unique aspect of the Joule-Thomson effect is the potential for temperature increase upon expansion, which contrasts with the behavior of ideal gases.
  • Additionally, a participant mentions the historical context, stating that the measurement of the Joule-Thompson coefficient contributed to the development of the absolute temperature scale.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the Joule-Thomson effect, particularly regarding temperature changes during adiabatic expansion. There is no consensus on the significance of the effect or its distinction from ideal gas behavior.

Contextual Notes

Some assumptions about the behavior of real gases versus ideal gases remain unaddressed, and the discussion does not resolve the nuances of isentropic versus general adiabatic processes.

jarman007
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It occurs when a real gas is allowed to expand adiabatically


we all know when a ideal gas is expanded adiabatically it temperature decreases
so real gas should do the same with minor difference




so what is all the fuss about we all know it will happen

why is it given a special name
 
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Question: did you look at wikipedia before posting?

jarman007 said:
we all know when a ideal gas is expanded adiabatically it temperature decreases
You seem to be thinking of isentropic, not general, adiabatic expansion.

jarman007 said:
so real gas should do the same with minor difference
so what is all the fuss about we all know it will happen
This can increase temperature.
 
So unique thing about joule thomson effect is increasing of temperature on expansion
 
In addition to the above comments, historically, measurement of the Joule-Thompson coefficient led to the development of the absolute (Kelvin) temperature scale.
 

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