1. Chem 125 Review 12/14/05 Projected material This material is for the exclusive use of Chem 125 students at Yale and may not be copied or distributed further. It is not readily understood without reference to notes from the lecture.

2. Functional Group Names RED: Memorize & Identify HOMO/LUMO BLUE: Memorize

3. Substitution of Cl for H H CH 3 Cl weak bond (58 kcal/mole) SOMO H Cl CH 3 Cl CH 3 Cl Cl single-electrons single-barbed arrows  "free-radical chain"

4. Cl **  C CH2H2 H2H2 + ** n + Addition of Cl 2 to an Alkene Cl C C H2H2 H2H2 C C H2H2 H2H2 (actually both steps at once) HOMO(  )LUMO(  *) HOMO(p) LUMO(p) New LUMONew HOMO-2 New HOMO-1 New HOMO  * F-CH 3

5. It is very common for an “electrophile” (LUMO) adding to the  HOMO of an alkene to come along with a HOMO that can react with the  * LUMO of the same alkene. This is the case in the previous example where the LUMO is the  * of Cl-Cl (or the vacant 2p orbital of Cl + ) and the HOMO is an unshared pair of Cl.

6. Ethers HOMO :O LUMO  * CO

7. Alkyl Halides Alcohols HOMO :X LUMO  * CX HOMO :O LUMO  * OH (or  * CO )

8. Aldehydes / Ketones R R O - Y: R R O Y - Addition of HY to C=O H __ Y - Y: R R OH Y HOMO :O LUMO  * C=O

9. Imines Boranes Like C=O HOMO :N LUMO  * HOMO  B-H LUMO 2p B

10. Carboxylic Acids Acidic because RCOO - has better HOMO-LUMO mixing (resonance stabilization) than RCOOH.

11. Acid Derivatives All have an X group attached to C=O that can leave as a reasonable anion. R X O - Y: R X O Y - R Y O X-X- reverse or Substitution of Y for X

12. I think I have fixed the following frame from the lecture of 11/16/05 so that it works with other browsers. [No one had told me of the problem until day before yesterday. Let me know when something fails.]

13. CIP (R/S) Nomenclature for Stereogenic Centers (S) inister (left) 4 3 2 1 1 3 4 2 (2R,3R)- 2,3-dihydroxy butanedioic acid right turn H (R) ectus (right) H Jones Sec. 4.4 pp. 157-161 H left turn H 1 4 2 3 CH 3 HO D H H D

14. Why Maxwell’s velocity distributions are different in 1, 2, and 3 Dimensions. (a minor point for Chem 125)

15. James Clerk Maxwell (1831-1879) Distribution of Velocities On the Motions and Collisions of perfectly elastic Spheres (1859) to find: f (v x ) probability of x-velocity between v x and v x + d v x

16. vxvx vzvz vyvy v (Total velocity) v 2 = v x 2 + v y 2 + v z 2 Assume v x, v y, v z are independent (meaning that joint probability is a product) g(v x 2 + v y 2 + v z 2 ) = f(v x ) f(v y ) f(v z ) Product Sum g(v x 2 + v y 2 + v z 2 ) = c 3 e -a (v x 2 + v x 2 + v x 2 ) f(v x ) = c e -a v x 2

17. f(v) = C v 2 e -a v 2 vxvx vzvz vyvy v Note that for a certain magnitude of v, the little dx  dy  dz box, in which we have reckoned probability, could be anywhere on the surface of a sphere of radius v. The area of this surface is proportional to v 2.

18. f(v) = C v 2 e -a v 2 v f(v) 1D 2D 3D Maxwell Velocity Distribution