Question

1 mole of an ideal gas at ${25}^{\circ }C$ is subjected to expand reversibly ten times of its initial volume. The change in entropy due to expansion is:

• A. $19.15J{K}^{-1}{\text{mol}}^{-1}|$
• B. $16.18J{K}^{-1}{\text{mol}}^{-1}|$
• C. $22.15J{K}^{-1}{\text{mol}}^{-1}|$
• D. $\text{none of these}$

Answer 1

The correct option is A $19.15J{K}^{-1}{\text{mol}}^{-1}|$

The entropy change for isothermal process is given as:

$\Delta S=2.303nRlog\frac{V_2}{V_1}$
as entropy change per mole is asked so
$\Delta S=2.303Rlog\frac{V_2}{V_1}$
putting the values, we get:

$\Delta S=2.303\times 8.314\times \text{log}10=19.15J{K}^{-1}{\text{mol}}^{-1}$