# Problem: Calculate the boiling point of benzene (C6H6). Round to nearest degree Celsius.

###### FREE Expert Solution

The vaporization of benzene involves the following reaction

C6H6(l)  C6H6 (g)

where

ΔSvap = entropy of vaporization

ΔHvap = enthalpy of vaporization

Tb = normal boiling point

Step 1: For ΔH˚vap:

We can use the following equation to solve for ΔH˚vap:

Note that we need to multiply each ΔH˚f by the stoichiometric coefficient since ΔH˚f is in kJ/mol. Also, note that ΔH˚f for elements in their standard state is 0.

We are given:

ΔH°, C6H6 (l) = 49.1 kJ/mol

ΔH°, C6H6 (g) = 82.9 kJ/mol

So the enthalpy of vaporization

ΔH°vap = 33.8 kJ/mol

Step 2: For ΔS˚vap:

We can use the following equation to solve for ΔS˚vap:

Note that we need to multiply each S˚ by the stoichiometric coefficient since S˚ is in J/mol • K. We also need to convert ΔS˚rxn from J/mol • K to kJ/ mol • K so our units remain consistent.

We are given:

S°, C6H6 (l) = 173.4 J/mol-K

S°, C6H6 (g) = 269.2 J/mol-K

So the enthalpy of vaporization

ΔS°vap = 0.0958 kJ/mol-K

Step 3: We can derive the normal boiling from:

We substitute the values we calculate

ΔHvap = 33.9 kJ/mol

ΔSvap= 0.0958 kJ/mol-K

###### Problem Details

Calculate the boiling point of benzene (C6H6). Round to nearest degree Celsius.