The document discusses intermolecular forces and their effect on solubility. There are three main types of intermolecular forces: London dispersion forces, dipole-dipole interactions, and hydrogen bonding. London dispersion forces are the weakest, while hydrogen bonding is the strongest. Compounds with stronger intermolecular forces have higher melting and boiling points, making them more likely to be liquids or solids rather than gases.

1. Tuesday review sessionOctober 4, 2010Intermolecular Forces and Solubility

2. Intermolecular ForcesDefinition: Forces between moleculesIntermolecular forces are much weaker than intramolecular forcesThere are three different typesLondon Dispersion Forces/ Van der WaalsDipole-Dipole InteractionsHydrogen Bonds

3. London Dispersion ForcesAlso referred to as Van der Waals forcesOccurs because of momentary dipole (uneven distributions of electrons in a molecule causing a partially negative end and a partially positive end)These are the weakest intermolecular forces

4. Dipole-Dipole InteractionsOccurs when polar molecules align so that their oppositely charged ends are attract each otherThis bond is stronger than Van der Waals forces

5. Hydrogen BondingA type of dipole-dipole bond that occurs when hydrogen is bonded to a highly electronegative atom (O, F, N)This is the strongest intermolecular force

6. Intermolecular Forces TrendsCompounds with stronger intermolecular forces will be harder to separate therefore they will have larger melting points and boiling pointsThis means compounds with weak intermolecular forces are more likely to be found in gaseous form, while compounds with stronger molecular forces are more likely to be found as liquids or solids