8.4 Water molecules move freely between the quid and gaseous phases ① Liquid water molecule② Liquid water cooled as③ Molecule enter9 gaseous Liquid water Water vapor ergy to overcome water molecule Figure 8.21 surface hydrogen bonding approaches liquid sur face e liquid surface. Air is The exchange of molecules at the interface between liquid and gaseous water. slowly moving gaseou8.4 Water molecules move freely between the liquid and gaseous phases