CHEM 110 Chapter Notes - Chapter 12: Enthalpy, Ionic Compound, Lattice Energy

• School: McGill University
• Department: Chemistry
• Course: CHEM 110
• Professor: Bryan Sanctuary

Document Summary

12. 1: intermolecular forces: van der waals forces. The term van der waals forces is used to describe, collectively intermolecular forces of the london type and interactions between permanent dipoles. Definition: polarizability is the term to describe the relative tendency for a charge distribution to distort from its normal shape in an atom or a molecule. Dipole-dipole interactions: in a polar substance, the molecules have permanent dipole moments, so the molecules tend to line up with the positive end of one dipole directed toward the negative ends of neighbouring dipoles. Dipole-induced dipole: a polar with a non-polar. The polar molecule induces a temporary dipole in the non-polar molecule. Forces: dispersion forces exist between all molecules, dispersion (london) forces are intermolecular forces associated with instantaneous and induced dipoles. An instantaneous dipole is when a non-polar species become momentarily polar when the electrons are concentrated in one region of an atom or a molecule.