Methanol, CH3OH, a colorless, volatile liquid, was formerly known as wood alcohol. It boils at 65.0°C and has a heat of vaporization of 37.4 kJ/mol. What is its vapor pressure at 22.0°C?

Answer 1

Use the Clausius-Clapeyron equation.
p1 = 760 mm
T1 = 65.0 + 273.15

P2 = unknown
T2 = 22.0 + 273.15
delta Hvap = 37400 J/mol

REMEMBER: The vapor pressure of a liquid at its boiling point is ALWAYS atmospheric pressure and standard pressure is 760 mm.

Answer 2

109 mmHg