Reversibiliteet

Reversibiliteet refers to the property of a process or reaction that can be reversed without leaving any permanent change in the surroundings. In a reversible process, the system can be restored to its original state by reversing the direction of the change, and the surroundings are also returned to their initial condition. This implies that no net work is done on or by the system, and no net heat is transferred to or from the surroundings over a complete cycle.

In thermodynamics, a reversible process is an idealized concept. Real-world processes are typically irreversible to some extent due to factors like friction, heat dissipation, and mixing. The concept of reversibility is crucial for understanding concepts like entropy and the limits of efficiency in engines and other thermodynamic devices.

A reversible process is considered to occur infinitesimally slowly, allowing the system and its surroundings to remain in equilibrium throughout the change. For example, a reversible expansion of a gas would involve a series of tiny, incremental increases in volume, with the external pressure always infinitesimally less than the internal pressure of the gas.

The total entropy change of an isolated system undergoing a reversible process is zero. For irreversible processes, the total entropy of the universe always increases. Therefore, reversibility is a benchmark for theoretical maximum efficiency and minimum energy dissipation.