Reversible vs irreversible

[Artin Allahverdian 2H]

What exactly is meant by a “reversible” process or an “irreversible” process in the context of thermodynamics?

[Celine Hoh 2L]

In thermodynamics, a reversible process is a process whose direction can be "reversed" by inducing infinitesimal changes to some property of the system via its surroundings. Throughout the entire reversible process, the system is in thermodynamic equilibrium with its surroundings. Having been reversed, it leaves no change in either the system or the surroundings.
Irreversible processes, on the other hand, are a result of straying away from the curve, therefore decreasing the amount of overall work done; an irreversible process can be described as a thermodynamic process that departs from equilibrium. Irreversibility is defined as the difference between the reversible work and the actual work for a process. When described in terms of pressure and volume, it occurs when the pressure (or the volume) of a system changes so dramatically and instantaneously that the volume (or the pressure) does not have time to reach equilibrium.

[Cynthia Aragon 1B]

A reversible process in thermodynamics refer to a process than can turn back in a way that both the system and the surroundings return back to their original states with no change occurring in the universe. Both the system and surroundings are returned to their initial states at the end of the reverse process.

An irreversible process is one that departs from equilibrium. In terms of pressure and volume, it happens when the pressure or the volume of a system changes so quickly that the volume or the pressure do not have the time to reach equilibrium. An example of an irreversible process is letting a certain volume of gas to release into a vacuum. By releasing pressure on a sample and allowing it to occupy a bigger space, the system and surroundings are not in equilibrium during the expansion process.

[Letizia Ye 4F]

Irreversible processes have changes in pressure and volume that occur so drastically that the system does not have enough time to reach equilibrium, and thus the system and surroundings are not at equilibrium while work is being done. However, since reversible processes occur with an infinite amount of small changes, it allows both the system and surroundings to remain in equilibrium. Reversible processes also do more work since less energy is lost as heat, but because of this the process can be very slow trying to conserve efficiency.