Question about the Zeroth law of thermodynamics and Equlibrium

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Discussion Overview

The discussion revolves around the Zeroth law of thermodynamics and the concept of equilibrium between two systems when separated by an adiabatic wall. Participants explore the implications of this separation on the state variables of the systems involved.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant asserts that if two systems A and B are in equilibrium, their coordinates (or state variables) do not change, but questions arise when they are separated by an adiabatic wall.
  • Another participant requests clarification on the term "coordinates," suggesting that they are more commonly referred to as 'state variables' such as temperature, pressure, and volume.
  • A participant notes that the state of the systems may drift apart after separation, depending on the surrounding conditions and whether there is a net flow of mass or energy across the separating wall.
  • There is an acknowledgment that the drift of states after separation is contingent on the environmental factors affecting the systems.

Areas of Agreement / Disagreement

Participants express differing terminology regarding the description of system states, with some using "coordinates" and others preferring "state variables." The discussion also indicates that there is no consensus on the specific effects of separation on the systems' states, as it is dependent on external conditions.

Contextual Notes

There is a lack of clarity regarding the definitions and implications of "coordinates" versus "state variables," and the discussion does not resolve the conditions under which the states may drift apart.

MatinSAR
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TL;DR
Question about zero law of thermodynamics and equilibrium
I know that if 2 systems A and B are in equilibrium their coordinates doesn't change. Systems are not complicated and be fully described using two separated coordinates X and Y.

What will happen if I seprate them using an adiabatic wall? Their coordinates start to change but I cannot understand why.
 
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I don't understand your use of the word "coordinates" here. Can you expand?
 
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DrClaude said:
I don't understand your use of the word "coordinates" here. Can you expand?
I've read about them in "Heat and Thermodynamics by M. W. Zemansky".
By coordinates I meant quantities that describe a state of a system like: Temperature, Pressure, Volume.

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Edit : Adding a picture of the book.
 
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Interesting, I know these as 'state variables', not coordinates.

If you separate two systems that are at first in equilibrium, then their state may or may not drift away from each other. This depends entirely on the surroundings they are in. If there is a net flow of mass or energy over the surface by which you separate the system, then this energy or mass flow stops after the separation. This will then influence the state of both systems, and their respective states will likely drift away from each other.
 
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Arjan82 said:
If you separate two systems that are at first in equilibrium, then their state may or may not drift away from each other. This depends entirely on the surroundings they are in.
I understand ... Thank you.
 

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