Question

Calculate the total entropy change for the transition at 368 K of 1 mol of sulphur from the monoclinic to the rhombic solid state and $\Delta$H = – 401.7 J mol–1 for the transition. Assume the surroundings to be an ice-water. Both at 0⁰C :

• A. – 1.09 JK–1
• B. 1.47 JK–1
• C. 0.38 JK–1
• D. None

Answer 1

Answer: (C)

0.38 JK–1

Answer 2

$\Delta$S(system) = $\frac{1 \times - 401.7}{368}$= – 1.09 JK–1

The ice-water both absorbs the 401.7 J mol–1 at temperature 273 K

$\therefore$ $\Delta$Ssurrounding = $\frac{1 \times 401.7}{273}$= 1.47 JK–1 and $\Delta$

S(universe) = – 1.09 + 1.47 = 0.38 JK–1