The vapor pressure data for an unknown liquid at 50 °C was 13.3 kPa and at 120 °C was 107 kPa.What is the value of ∆Hvap for this gas?

Question

Chemistry II Question

Answer 1

Clausius Clapeyron equation:

ln (P2/P1) = -∆H/R (1/T2 - 1/T1)

P1 = 13.3 kPa

P2 = 107 kPa

T1 = 50C + 273 = 323K

T2 = 120C + 273 = 393K

R = 8.314 J/Kmol

∆H = ?

ln ( 107 / 13.3) = -Ea/8.314 (1/393 - 1/323)

2.085 = 0.0005515Ea / 8.314

∆H = 31432 J