The change in internal energy of gas in the process BC is — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

Internal energy change for the monoatomic ideal gas from B ($200\text{ K}$) to C ($400\text{ K}$) is $\Delta U_{BC} = n C_v \Delta T = 1 \times (\frac{3}{2} R) \times (400 - 200) = 1.5 \times 8.314\text{ J/K-mol} \times 200\text{ K} = 2494.2\text{ J} \approx 2.49\text{ kJ}$.