For a particular liquid,raising its temperature from 331 K to 351 K causes its vapor pressure to double.What is the enthalpy of vaporization of this liquid? (R = 8.314 J/K · mol)
A) 34 kJ/mol
B) 288 kJ/mol
C) 2 kJ/mol
D) 244 kJ/mol
E) 115 kJ/mol

Question

Quizplus · Accepted Answer

The enthalpy of vaporization can be calculated using the Clausius-Clapeyron equation: $\Delta H_{vap} = \frac{R \cdot \Delta T \cdot \ln(\frac{P_2}{P_1})}{\frac{1}{T_1} - \frac{1}{T_2}}$, where $P_2/P_1 = 2$ (vapor pressure doubles), $T_1 = 331 K$, $T_2 = 351 K$, and $R = 8.314 J/K \cdot mol$. Plugging these values in, we find $\Delta H_{vap} \approx 34 kJ/mol$.

For a Particular Liquid,raising Its Temperature from 331 K to 351