[pistaciolow]

What is the ΔH°vap (in J/mol) of a liquid that has a vapor pressure of 641 torr at 80.7°C and a boiling point of 96.7°C at 1 atm?



641 torr/760= .843 atm
80.7°C=353.7°C
96.7°C=369.7°C

ln(1 atm/.843 atm)=(x/8.314 J/mol*K)[(1/353.7K)-(1/369.7K)]
.17078=1.4717e-5(x)
x=11604.83 J
I put in 1.2e4 for sig figs and got this message:

Your answer is within 10% of the correct value.

Any ideas?