Clausius Clapeyron please help

Question

a handbook lists the normal boiling point of an organic liquid as 42.6 Celsius and it’s enthalpy of vaporizationas 24.9 kJ/mol. Calculate the vapor pressure in torr of this  compound at 25.0 celsiuS.

Answer 1

Clausius Clapeyron equation is used to determine the vapor pressure of a liquid when its boiling point and enthalpy of vaporization are known. It is written as

ln(P1/P2)= delta Hvap./R (1/T2 — 1/T1) where

P2 = unknown vapor pressure

P1 = vapor pressure at b.p. which is 1 atm because liq. boils when it’s vapor pressure equals atmospheric pressure which is 1

Delta Hvap = 24.9kj/mole or 29000j/mole

R. = 8.314j/Kmole

T2 = 25+273=298K

T1 =42.6+273= 315.6K. Change temp into Kelvin

Sustitute values

ln(1/P2)= 24900/8.314 (1/298 —1/315.6)

1/P2 = e^.5600

P2. = 0.57atm. Change to torr

= .57×760 = 434 torr