Adiabatic process

Definition

An adiabatic process is a thermodynamic process in which no heat is exchanged with the surroundings. In such processes, changes in internal energy are solely due to work done by or on the system.

5 Must Know Facts For Your Next Test

1. In an adiabatic process, $Q = 0$, where $Q$ denotes heat exchange.
2. The first law of thermodynamics for an adiabatic process simplifies to $\Delta U = -W$, where $\Delta U$ is the change in internal energy and $W$ is the work done by the system.
3. Adiabatic processes can occur rapidly so that there is no time for heat exchange.
4. For an ideal gas undergoing an adiabatic process, the relation between pressure and volume is given by $PV^\gamma = constant$, where $\gamma$ (gamma) is the heat capacity ratio ($C_p / C_v$).
5. In a reversible adiabatic process, also known as an isentropic process, entropy remains constant.

Review Questions

• What condition must be met for a thermodynamic process to be considered adiabatic?
• How does the first law of thermodynamics simplify for an adiabatic process?
• What equation relates pressure and volume for an ideal gas during an adiabatic process?

Related terms

Isothermal Process: A thermodynamic process in which the temperature remains constant.

Isobaric Process: A thermodynamic process that occurs at a constant pressure.

Isochoric Process: A thermodynamic process that takes place at constant volume.