Thermodynamic Equilibrium - QS Study
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Thermodynamic Equilibrium

Final steady state of an isolated system is called thermodynamic equilibrium. At equilibrium thermodynamic coordinates. i.e., pressure, volume, and temperature are same at all points in the system.

For a thermodynamic equilibrium system with certain energy, the entropy is larger than that of any other state with the similar energy. For a thermodynamic equilibrium state with given pressure and temperature, the Gibbs free energy is lesser than that of any other condition with the similar pressure and temperature.

Situations of Thermodynamic Equilibrium

The system is said to be in thermodynamic equilibrium if the circumstances for following three equilibrium is fulfilled:

  • Mechanical equilibrium
  • Chemical equilibrium
  • Thermal equilibrium

Mechanical equilibrium: When there are no unstable forces within the structure and between the system and the surrounding, the system is said to be under mechanical equilibrium.

Chemical equilibrium: The system is said to be in chemical equilibrium when there are no chemical reactions going on within the system or there is no transfer of the substance from one part of the system to other due to diffusion.

Thermal equilibrium: When the system is in mechanical and chemical equilibrium and there is no impulsive modify in any of its properties, the system is said to be in thermal equilibrium.