Question

How much heat would be required to convert 234.3 g of solid benzene, C6H6(s), at 5.5 c into benzene vapor, C6H6, at 100 c?
mp of C6H6=5.5c bp of C6H6=80.1 c
mhc C6H6(l)=136J/mol*c
mhc C6H6(g)=81.6J/mol*c
mhfusion at 5.5 c=9.92kJ/mol
mhvaporization at 80.1 c= 30.8kJ/mol

Answer 1

Benzene must be melted, heat to boiling point, converted to vapor.

mass bz x heat fusion to melt it.
mass bz x specific heat x delta T to move it to the boiling point.
mass bz x heat vaporization to turn it into vapor.
mass bz x specific heat vapor x delta T to move vapor to 100.
Add the four steps together to obtain the total.