4AB › Chemistry PYQ › CSIR-NET › June 2019 › Q16Q16 · CSIR-NET Chemistry, June 2019 Paper: CSIR-NET June 2019 · Subject: Physical Chemistry · Chapter: Thermodynamics · Topic: Laws State Functions · Marks: 2 · Difficulty: Medium
A non-ideal gas, follows the equation \[ P=\frac{R T}{V_{m}}\left[1+\frac{B}{V_{m}}\right] \]
where $B$ is a function of temperature only. The deviation in internal energy from that of an ideal gas, $\mathrm{U}-U_{\text {ideal }}$ ideal is given by (a) $-\frac{R T}{V_{m}}\left(\frac{\partial B}{\partial T}\right)_{V}$
(b) $-\frac{R T^{2}}{V_{m}}\left(\frac{\partial B}{\partial T}\right)_{V}$
(c) $-\frac{R T^{2}}{V_{m}} B$
(d) $-\frac{R T}{V_{m}} B$
Answer Answer: B ✓ checked by 4AB · confidence high
Explanation (∂U/∂V)_T = T(∂p/∂T)_V − p = (RT²/V_m²)(dB/dT). Integrating from V_m = ∞ (ideal) to V_m gives U − U_ideal = −(RT²/V_m)(dB/dT).
← Q15 · All questions in this paper · Thermodynamics chapter list · Q17 → Study loop for Thermodynamics
Open in whiteboard · Browse this chapter in the app