An induced dipole can be created when a charged molecule comes near a neutral molecule (WaterontheWeb, 2004). The neutral molecule becomes more polar to reduce the effects of the charge on the other molecule and so becomes polarized itself. By rubbing the balloon on the body, it develops a positive charge which induces a negative dipole on the bodyÆs surface so the balloon is attracted to it in a dipole-dipole interaction.
Water has a permanent net dipole resulting from hydrogen being covalently bonded to oxygen (Intermolecular, 2004). Hydrogen bonds operate between water molecules, and they are stronger intermolecular forces than either dispersion forces or dipole-dipole interactions because the hydrogen nucleus is extremely small and positively charged, and oxygen is extremely electronegative. This causes the electron on the hydrogen atom to be strongly attracted to the oxygen, leaving a highly localized positive charge on the hydrogen atom, and a highly localized negative charge on the oxygen atom. AS a result, the electrostatic attraction between these molecules will be greater than for polar molecules that do not have hydrogen covalently bonded to oxygen, fluorine, or nitrogen.
Carbon dioxide experiences dispersion forces, which are very weak forces of attraction between molecules resulting from momentary dipoles due to uneven electron distributions in neighboring molecules as they approach each other, and the weak residual attraction of the nuclei in one molecule for the electrons in a neighboring molecule (Intermolecular, 2004). The dispersion forces will be stronger, the more residual electrons that are present in the molecule. Dispersion forces are the only intermolecular forces operating between non-polar molecules, such as carbon dioxide.
Melting and boiling points result from progressive weakening of the attractive forces between covalent molecules, so the stronger the intermolecular force that exists...