When an ideal diatomic gas is a heated at a constant pressure, the fraction of heat energy supplied — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

The fraction of heat used to increase internal energy at constant pressure is exactly $\frac{\Delta U}{q_p} = \frac{n C_v \Delta T}{n C_p \Delta T} = \frac{C_v}{C_p} = \frac{1}{\gamma}$. For a standard ideal diatomic gas without active vibrational modes, $\gamma = 7/5$, making the fraction $5/7$.