Question

The entropy change involved in the isothermal reversible expansion of 2 moles of an ideal gas from a volume of 10 dm3 to a volume of 100 dm3 at 27⁰C is :

• A. 38.3 J mol–1 K–1
• B. 35.8 J mol–1 K–1
• C. 32.3 J mol–1 K–1
• D. 42.3 J mol–1 K–1

Answer 1

Answer: (A)

38.3 J mol–1 K–1

Answer 2

$\Delta$S = nR ln $\frac{V_{2}}{V_{1}}$ = 2.303 nR log $\frac{V_{2}}{V_{1}}$

= 2.303 × 2 × 8.314 × log $\frac{100}{10}$= 38.3 J mol–1 K–1