The molar enthalpy of vaporisation (ΔHvap\Delta H_{\text{vap}}ΔHvap) of a liquid is the enthalpy change when one mole of liquid is converted to vapour at its boiling point.
To determine ΔHvap\Delta H_{\text{vap}}ΔHvap for propanone (CH3COCH3\text{CH}_3\text{COCH}_3CH3COCH3), a student uses an electrical immersion heater to boil a sample of propanone in a flask. The system is maintained at the boiling point of propanone (56 ∘C56\text{ }^{\circ}\text{C}56 ∘C).
The student:
The loss in mass of propanone during this time is 515 g515\text{ g}515 g.
Calculate the molar enthalpy of vaporisation, ΔHvap\Delta H_{\text{vap}}ΔHvap, for propanone.
(Molar mass of propanone = 58.0 g mol−158.0\text{ g mol}^{-1}58.0 g mol−1)
[1 kW=1 kJ s−1][1\text{ kW} = 1\text{ kJ s}^{-1}][1 kW=1 kJ s−1]