Thermodynamic Equilibrium

A system is said to be in thermodynamic equilibrium, if it satisfied the following three requirements of equilibrium.

1. Mechanical equilibrium. A system is said to be in mechanical equilibrium, when there is no unbalanced forces acting on any part of the system.
2. Thermal equilibrium. A system is said to be in thermal equilibrium, when there is no temperature difference between the parts of the system.
3. Chemical equilibrium. A system is said to be in chemical equilibrium, when there is no chemical reaction with the system.