In a certain polytropic process the volume of argon was increased 4 times. Simultaneously, the press — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

$P_1 V_1^n = P_2 V_2^n \implies (P_1/8)(4V_1)^n = P_1 V_1^n \implies 4^n = 8 \implies 2^{2n} = 2^3 \implies n = 1.5$. Molar heat capacity $C = C_V + \frac{R}{1-n}$. For argon (monoatomic), $C_V = 1.5R$. $C = 1.5R + \frac{R}{1-1.5} = 1.5R - 2R = -0.5R = -0.5 \times 8.314 = -4.157\text{ J/K-mol}$.