Question

Calculate the total entropy change for the transition at $368K$ of $1mol$ of sulphur from the monoclinic to the rhombic solid state $(\Delta H=-401.7J{mol}^{-1})$. Assume the surrounding to be an ice-water both at $0^{0}C$.

• A. $-1.09J{K}^{-1}$
• B. $1.47J{K}^{-1}$
• C. $0.38J{K}^{-1}$
• D. None of these

Answer 1

The correct option is C $0.38J{K}^{-1}$

Using:

${\Delta S}_{\text{transition}}=\frac{{\Delta H}_{\text{transition}}}{T_{\text{transition}}}$

${\Delta S}_{surr}=\frac{{-\Delta H}_{trans}}{T}$

${\Delta S}_{trans}=\frac{-401.7}{368}$

${\Delta S}_{surr}=\frac{+401.7}{273},\because$ temperature of ice bath$=273K$

${\Delta S}_{Total}=\frac{-401.7}{368}+\frac{401.7}{273}=0.38J/K$