Which statement correctly describes what happens when a sample of liquid propanone, CH3COCH3\text{CH}_3\text{COCH}_3CH3COCH3, is vaporised at its boiling point?
Covalent C−H\text{C}-\text{H}C−H and C=O\text{C}=\text{O}C=O bonds within the propanone molecules are broken.
Hydrogen bonds and permanent dipole-dipole forces between the molecules are overcome.
Permanent dipole-dipole forces and London forces between the molecules are overcome.
The enthalpy of the substance decreases as the process is exothermic.
