text: Water, as a polar molecule, induces an accumulation of electron density (dipole moment) at one end of non-polar gas molecules such as oxygen (O2 ) and carbon dioxide (CO2 ). The electron cloud of O2 is normally distributed symmetrically between the bonded O2 atoms. When the negative end of the H2O molecule approaches the oxygen molecule, the electron cloud of the O2 moves away to reduce the negative-to-negative repulsion. A dipole (a molecule with positive and negative charges separated by a distance) results in the nonpolar O2 molecule and causes O2 and H2O to become weakly attracted to each other. This intermolecular attraction between the oppositely charged poles of nearby molecules is termed a dipole- dipole force. The creation of these forces explains the mechanism by which gases dissolve in water.