1. Lon-Capa 7th HW assignment due Friday, 11/11, by 5 pm.
5th Quiz due Sunday, 11/13 by 10 pm. It will open Friday, 11/11 at 5 pm.

4. Intermolecular Forces (IMFs)

5. London dispersion forces
All molecules exhibit these forces (all molecules have electrons and protons).
Due to temporary and induced dipoles.
Strongest IMFs for non-polar molecules
Examples of non-polar molecules include nitrogen (N2) and methane (CH4).

6. London Dispersion Forces (LDFs)

7. Dipole-dipole interactions
Polar molecules exhibit these forces.
Due to permanent dipoles.
Stronger IMFs than LDFs (given similar sized molecules).
Examples include hydrogen chloride (HCl) and water (H2O – which exhibits a special kind of dipole-dipole interaction called hydrogen bonding).

8. Dipole-Dipole Interactions

10. Hydrogen Bonding in Water

11. Ion-ion interactions Ionic compounds exhibit these forces.
Due to ions.
Strongest of the IMFs (given similar sized molecules).
Example includes sodium chloride (NaCl).

12. “Like Dissolves Like”

13. Another Question for the 2nd Law:
Why don’t oil and water mix?
“Like dissolves like”: why?
All molecules exhibit LDFs – shouldn’t they all be attracted to one another?

15. Non-ideal Behavior of Real Gases