Intermolecular Forces Essay examples

1012 Words Jun 14th, 2013 5 Pages
Intermolecular forces exist between independent particles, such as atoms, ions, or molecules. They can be forces of either attraction or repulsion. The amount of charge, how it is distributed, and the length of time that a charge distribution exists can affect the strength of intermolecular forces. And despite having variable force strengths, all intermolecular forces are considered weak compared to chemical bonds, or intramolecular forces. Chemical bonds are not only stronger; they are also more permanent. The energy costs involved in breaking chemical bonds are much higher than ones needed to overcome intermolecular forces.

There are five types of intermolecular forces: ion-ion forces, ion-dipole forces, ion-induced
…show more content…
Induced dipoles occur between polar and nonpolar molecules. If there were only nonpolar molecules, they would be London dispersion forces (but keep in mind that these forces also exist in every other kind of interaction). In the case of ion-ion forces, polarity does not matter in identifying forces, as it only involves ions and would be fairly obvious.

Knowing what we do about intermolecular forces and their relative strengths, we can make a few assumptions about which forces would be present in different phases under standard conditions. Being that solids are the most difficult to break apart, we would assume that the strongest intermolecular forces (ion-ion, hydrogen bonding) would be found within them. Liquids have a greater ability to flow because the intermolecular forces are weaker than in the solid phase, so we would assume that these would involve ion-dipole and induced dipole forces. We would also assume that the weakest intermolecular forces correspond to the gas phase, meaning dipole-dipole and London dispersion forces.

Intermolecular forces influence physical properties of each phase: gas, liquid, and solid. They can cause real gases to deviate from ideal gas behavior. They can also govern the motion of molecules; molecules in gases move constantly and randomly, they slide past each other freely in liquids, and vibrate in fixed positions in solids. The heats required to melt a solid (heat of fusion) and to vaporize a

Related Documents