Question

One mole of a perfect gas expands isothermally to tentimes its original volume. The change in entropy is

• A. 0.1 R
• B. 2.303 R
• C. 10.0 R
• D. 100.0 R

Answer 1

Answer: (B)

2.303 R

Answer 2

$q_{rev} = - W_{rev} = 2.303$ nRT log $\frac{V_2}{V_1}$ $\Delta S = \frac{q_{rev}}{T}$ = 2.303 nR log $\frac{V_2}{V_1}$ Here n = 1, $\frac{V_2}{V_1} = 10$ $\therefore$ $\Delta S = 2.303 \times 1 \times R \times log \, 10$ = $2.303 \times R \times 1 = 2.303$ R