1. Lecture 20: Intermolecular Forces and Condensed Phases
What causes molecules (or atoms or ions or …) to stick to each other?
Potential energy curves
Phase Diagrams: Single components vs. the “real” world

2. Van der Waals
Equation of State

3. Predict which a cation of sodium is most strongly attracted to:
Br- anion
HBr molecule
Kr atom
H2O molecule

4. Predict which an atom of hydrogen is most strongly attracted to:
Br- anion
Na+ cation
H2 molecule
Kr atom
H atom
H2O molecule

5. Relative strength of interatomic/intermolecular forces:
Ion – Ion (charge matters!)
Open-shell atom – Open-shell atom (covalent bonds matter!)
Ion – Dipole (dipoles matter!)
Dipole – Dipole Special Case: Hydrogen Bond
Ion – Induced dipole
Dipole – Induced dipole
Fluctuating dipole – induced dipole (“dispersion force”)

6. Which is lower in energy?
(1) (2)

7. Potential Energy Curves

9. 1mL of liquid water is placed into an evacuated container of volume 10mL at room temperature. What is the pressure?
10atm
1atm
0.1atm
0.01atm
0.000atm