Answer:
24.895 kJ/mol
Explanation:
The expression for Clausius-Clapeyron Equation is shown below as:
[tex]\ln P = \dfrac{-\Delta{H_{vap}}}{RT} + c [/tex]
Where,
P is the vapor pressure
ΔHvap is the Enthalpy of Vaporization
R is the gas constant (8.314 J /mol K)
c is the constant.
For two situations and phases, the equation becomes:
[tex]\ln \left( \dfrac{P_1}{P_2} \right) = \dfrac{\Delta H_{vap}}{R} \left( \dfrac{1}{T_2}- \dfrac{1}{T_1} \right)[/tex]
Given:
[tex]P_1[/tex] = 271.2 mmHg
[tex]P_2[/tex] = 641.8 mmHg
[tex]T_1[/tex] = 241.3 K
[tex]T_2[/tex] = 259.3 K
So,
[tex]\ln \:\left(\:\frac{271.2}{641.8}\right)\:=\:\frac{\Delta \:H_{vap}}{8.314}\:\left(\:\frac{1}{259.3}-\:\frac{1}{241.3}\:\right)[/tex]
[tex]\Delta \:H_{vap}=\ln \left(\frac{271.2}{641.8}\right)\frac{8.314}{\left(\frac{1}{259.3}-\:\frac{1}{241.3}\right)}\ J/mol[/tex]
[tex]\Delta \:H_{vap}=\left(-\frac{520199.41426}{18}\right)\left(\ln \left(271.2\right)-\ln \left(641.8\right)\right)\ J/mol[/tex]
ΔHvap = 24895.015 J/mol = 24.895 kJ/mol ( 1 J = 0.001 kJ )
