What is the molar heat capacity of gas in this process? — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

The passage defines the condition $q = -\Delta U$. For a molar thermodynamic process, $q = n C \Delta T$ and $\Delta U = n C_{v,m} \Delta T$. Equating these yields $n C \Delta T = -n C_{v,m} \Delta T$, leaving $C = -C_{v,m}$.