For which of the following ideal gas, is independent of temperature? — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

For monoatomic ideal gases (like helium, He), there are only 3 translational degrees of freedom which are always active, so $C_v$ = 1.5 R is completely independent of temperature. Diatomic and polyatomic gases (like $H_2$, $CO$, $SO_2$) have rotational and vibrational degrees of freedom that become active at different temperatures, making their heat capacities temperature-dependent.