Which of the following sets of thermodynamic conditions accurately describes the spontaneous free ex — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

In free expansion, the gas expands strictly against a vacuum, meaning external pressure $P_{ext} = 0$. As a result, work done $w = -P_{ext}\Delta V = 0$. The process happens in an insulated container, enforcing adiabatic conditions where $q = 0$. According to the First Law ($\Delta U = q + w$), $\Delta U = 0$. Finally, for ideal gases $\Delta U = nC_v\Delta T$, which dictates $\Delta T = 0$ (no temperature change).