Question

Two mole of an ideal gas is expanded irreversibly and isothermally at ${37}^{\circ }C$ until its volume is doubled and $3.41$ kJ heat is absorbed from surrounding. $\Delta S_{total}$ (system + surrounding) is :

• A. $-0.52$ J/K
• B. $0.52$ J/K
• C. $22.52$ J/K
• D. $0$

Answer 1

The correct option is B $0.52$ J/K

$\Delta S_{total}=\Delta S_{system}+\Delta S_{surrounding}$

$\Delta S_{system}=R\ln \frac{V_2}{V_1}=-2.303R\ln \frac{2}{1}$

$\Delta S_{system}=-2.303\times 8.314\times 0.301=-5.76kJ$

$\Delta S_{surrounding}=2\times 3.41=6.82kJ$

$\Delta S_{total}=\frac{6.82-5.76}{2}=0.52kJ$