Announcements Be respectful – no electronics please! Exam 3 is on Thursday April 25 at 7:00 pm! (Conflict at 5:00 pm, sign up in 1026 Chem Annex before NOON next Thurs) No calculators allowed Exam room locations posted online Q & A TA Review Sessions posted online starting Monday Lab due tomorrow in discussion Pre-lecture assignments due Tuesdays & Thursdays at 8 am as usual. Workshop 2 is due at the beginning of class on Monday (no textbook problems) Start Exam 3 Review Questions in discussion tomorrow and lab on Monday, due Wednesday at 10 pm Last Lon-Capa HW due Wednesday at 10 pm

Clicker #1: Check in from Tuesday The molecules KrCl2 and KrF2 have… The same geometry, same shape, and are both polar. The same geometry, same shape, and are both nonpolar. The same geometry, different shape, and are both polar. The same geometry, different shape, and are both nonpolar. Different geometries, different shapes, and are both polar.

Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure Molecular Properties

Oil Structure vs. Water Structure Polar Nonpolar

Gulf of Mexico Shell Oil Spill, 2010

Clicker #2: Will CH3OCH3 dissolve in water? No, because it is nonpolar. Yes, because it has a dipole moment pointing towards the carbons. Yes, because it has a dipole moment pointing towards the oxygen.

Question Which of the following has the strongest intermolecular forces? 1) Cl2 2) Br2 3) I2 4) All of the above have the same amount of intermolecular forces.

Question Which of the following has the strongest intermolecular forces? 1) H2O 2) SF6 3) Both have the same amount of intermolecular forces.

Clicker #3 How many of the following interactions does CH3CH2OH exhibit? London dispersion dipole-dipole hydrogen bonding A) 0 B) 1 C) 2 D) 3

Clicker #4 How many of the following interactions does CH3OCH3 exhibit? London dispersion dipole-dipole hydrogen bonding A) 0 B) 1 C) 2 D) 3

Clicker #5 Choose the molecule with the highest boiling point. (Hint: Is each polar or nonpolar?) a) SeO3 b) SeO2 c) H2