Question

A system in thermodynamic equilibrium satisfies the following requirements:

• A. A system is in mechanical equilibrium
• B. A system is in mechanical equilibrium and chemical equilibrium
• C. A system is in mechanical equilibrium and thermal equilibrium
• D. A system is in mechanical equilibrium, chemical equilibrium and thermal equilibrium

Hint:

Note that a system must be in mechanical, thermal and chemical equilibrium simultaneously to reach the thermodynamic equilibrium. If any of the equilibriums is not met, the system cannot be in the thermodynamic equilibrium.

Answer 1

The Correct Option is D

Thermodynamic equilibrium refers to a state where a system’s macroscopic properties do not change over time. This state is achieved when a system has reached a balance in several different aspects of its energy and matter exchange with its surroundings, and its components. These aspects are captured by three primary types of equilibrium:
• Mechanical Equilibrium: This means that there are no net forces acting on the system or its parts. There are no pressure gradients. In a closed system, it implies that the pressure is uniform throughout.
• Chemical Equilibrium: This means that there are no changes in the chemical composition of the system. The net rate of all chemical reactions is zero. This means there is no further net conversion of reactants to products or vice-versa
• Thermal Equilibrium: This means that the temperature of the system is uniform through-out and the system is at the same temperature as its surroundings. There is no further net heat exchange between the system and its surroundings or different components within it.
For a system to be in full thermodynamic equilibrium, it must satisfy all three of these conditions simultaneously.