ACS Physical Chemistry: Thermochemistry 2026 – 400 Free Practice Questions to Pass the Exam

The relationship \( pV^\gamma = \text{constant} \) is derived from the ideal gas law and is specifically applicable to adiabatic processes involving an ideal gas. In this context, \( p \) represents the pressure, \( V \) stands for the volume, and \( \gamma \) is the heat capacity ratio (the ratio of specific heat at constant pressure to specific heat at constant volume, \( C_p/C_v \)).

This equation indicates that for an ideal gas undergoing an adiabatic process, as the volume changes, the pressure adjusts in such a manner that the product of pressure and volume raised to the power of \( \gamma \) remains constant. This relationship highlights the interplay between pressure and volume during adiabatic changes; as one parameter decreases, the other must correspondingly change to maintain the constant value defined by the equation.

In this context, the emphasis is on the specific interaction between pressure and volume rather than their individual relationships with temperature, heat capacity, or other thermodynamic quantities. Thus, the connection described in \( pV^\gamma = \text{constant} \) directly links pressure to volume under adiabatic conditions in thermodynamics.