liquid has an enthalpy of vaporization of 30.8 kJ/mol. At 273 K it has a vapor pressure of 102 mmHg. What is the normal boiling point of this liquid? (R = 8.31 J/(K.mol)a. 257kb. 238kc.273kd.292ke.320k

Respuesta :

Answer:

Option E is correct. 320K

Explanations:

In order to get the normal boiling point of the liquid, we will use the Clausius-Clapeyron equation expressed according to the equation:

[tex]\ln (\frac{P_2}{P_1}_{})=-\frac{\triangle H_{vap}}{R}\cdot(\frac{1}{T_2}-\frac{1}{T_1})[/tex]

where:

P1 is the vapor pressure of that substance at T1

P2 is the vapor pressure of that substance at T2

ΔHvap is the enthalpy of vaporization.

R is the gas constant - usually expressed as 8.314J/Kmol

Given the following parameters:

[tex]\begin{gathered} P_1=102\operatorname{mm}Hg \\ P_2=760\operatorname{mm}Hg(cons\tan t) \\ T_1=273K \\ \triangle H_{\text{vap}}=30.8\text{kJ/mol} \\ R=8.31\text{J/Kmol} \end{gathered}[/tex]

Substitute the given parameters into the formula to get T2

[tex]\ln (\frac{760_{}}{102_{}}_{})=-\frac{30.8\times10^3\frac{J}{mol}_{}}{\frac{8.31J}{\operatorname{km}ol}}\cdot(\frac{1}{T_2_{}}-\frac{1}{273_{}})[/tex]

Simplify the result to get the value of T2

[tex]\begin{gathered} \ln (7.4509)=-3,706.3778(\frac{1}{T_2}-\frac{1}{273}) \\ 2.0083=\frac{-3,706.3778}{T_2}+13.5765 \\ \frac{-3,706.3778}{T_2}=2.0083-13.5765 \\ \frac{-3,706.3778}{T_2}=-11.5682 \\ -11.5682T_2=-3,706.3778 \\ T_2=\frac{-3,706.3778}{-11.5682} \\ T_2=320.39K \\ T_2\approx320K \end{gathered}[/tex]

Hence the normal boiling point of this liquid is approximately 320K