What are the correct conditions for the free expansion of an ideal gas under adiabatic conditions? — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

In an adiabatic process, heat exchange $q = 0$. Free expansion occurs against a vacuum ($P_{ext} = 0$), resulting in work done $w = -P_{ext}\Delta V = 0$. According to the First Law ($\Delta U = q + w$), $\Delta U = 0$. For an ideal gas, $\Delta U = nC_v\Delta T$, which implies $\Delta T = 0$.