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Factors Affecting Dissolving Power

As mentioned earlier, a solvent's ability to dissolve a solute is dependent upon how similar it's electrostatic forces are to those of the solute.  There are three component forces that make up these van der Waals forces.  These component forces are dispersion forces, polar forces and hydrogen bonding forces.

Dispersion Forces

Dispersion forces are caused by the temporary attractions generated by the dynamic nature of electron orbits.  Because electrons vary their paths as they circle the nucleus, pockets of electrostatic force are created on the surface of a molecule whenever a nucleus is temporarily exposed by the dispersed electrons.  Dispersion forces are size dependent; the larger the molecule, the stronger the bond between molecules.

Polar Forces

Polar forces are dependent upon molecular characteristics such as atomic composition, geometric shape and size.  Some molecules have areas of their surface with a permanent electrostatic force which causes them to attract other molecules.  Molecules that display these constant electrostatic attractions are called polar molecules.  Polar molecules vary in the strength of their electrostatic forces because molecules vary in the characteristics that generate these forces.

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