CHEM 333 Lecture Notes - Lecture 6: Arrow Pushing, Boiling Point, Lone Pair
15 Sep 2016
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Amides: derivative of carboxylic acid o o. Classified based on number of carbons attached to n. Intermolecular forces affect melting point and boiling point. Strong electrostatic force between positive and negative ions: need a large amount of energy to break apart in solid state. Van der waals forces: dipole-dipole- some molecules are polar (have permanent dipoles); orient so plus of one molecule interacts with negative of another. Higher boiling point vs. not having this interaction: hydrogen bonds- strong interaction between a heteroatom with a hydrogen and a heteroatom with a lone pair (o, n, f, s, cl, br, i) Weaker than covalent bonds; stronger than dipole/dipole: dispersion forces. Molecules attracted to one another for a short bit of time. Get a small dipole spontaneously (but fleeting) > moves near another molecule and induces a small dipole in another molecule. Small molecules have less surface area, so less attraction. Large molecules have more surface area, so more attraction.
