How do I calculate the normal boiling point of CCl4?

Question

CCl4 has a vapor pressure of 213 torr at 40°C and 836 torr at 80°C. What is the normal boiling point  CCl4?

Answer 1

Use the Clausius-Claperyon equation and solve for ∆Hvap.

ln P1/P2 = ∆Hvap/R (1/T2 - 1T1)

P1 = 213 torr

T1 = 313 K

P2 = 836 torr

T2 = 353 K

R = 8.314 kJ/mol-K

Solve for ∆Hvap which will have units of kJ/mole

 

Use the ∆Hvap and plug into the C-C equation again, and solve for T2 using P2 = 760 torr and either set of P and T from the original question.