According to Wiki, the heat of vaporisation of methanol is +35.28 kJ/mol. Let’s say I put some methanol in a flask, and measured the pressure at various temperatures. For example, at 19.9ºC, the total pressure is 113.49 kPa and the air pressure is 104.49 kPa, so the vapour pressure of the methanol is 9.07 kPa. At 52.8ºC, the vapour pressure is 40.79 kPa.
How do I approach the problem of finding the enthalpy of vaporisation? That is, how do I find out the value of ∆H[sub]vap[/sub]?