Equilibrium in thermodynamics is defined as which of the following?

Equilibrium in thermodynamics is defined as which of the following?

• A. A dynamic state in which macroscopic properties do not change with time
• B. A static condition in which no changes occur in the macroscopic properties with time
• C. A condition where all processes are irreversible
• D. A state with zero energy change

Answer: (B)

Equilibrium means the system’s observable macroscopic properties stay the same with time because all driving forces are balanced. In practice, microscopic processes can continue (dynamic equilibrium), but there is no net change in the values we measure. This is why describing equilibrium as a static condition where macroscopic properties do not change over time is a useful and accurate way to capture the idea. Energy can flow in or out while the overall state remains constant, and many equilibrium processes are reversible, not irreversible.

Equilibrium means the system’s observable macroscopic properties stay the same with time because all driving forces are balanced. In practice, microscopic processes can continue (dynamic equilibrium), but there is no net change in the values we measure. This is why describing equilibrium as a static condition where macroscopic properties do not change over time is a useful and accurate way to capture the idea. Energy can flow in or out while the overall state remains constant, and many equilibrium processes are reversible, not irreversible.