NAME _______________________ CHEM 311 EXAM I Fall 2001 Sect 002
1. Draw the electronic configuration of S 1s2
S has ______ valence electrons and ( adds, gives up ) _____ electrons to
become a stable octet.
a. (CH3)3 NH+1 + CH3-O-1 « +
(acid, base) (acid, base) conjugate + conjugate (acid, base) (acid, base)
____b. alcohol ____g.amine 2. RNH2 7. RCH=CHR’
____c. alkyne ____h. ester 3. RCOOH 8. RC=OOR’
____d. aldehyde ____i. alkyl halide 4. RCl 9. ROH
____e. nitrile ____j. carboxylic acid 5. RC=O NH2 10. RCN
b. Indicate the hybridization and geometry of each carbon atom.
dioxide ( SO2 ) has a
dipole of 1.6 D while carbon dioxide (
has a dipole of 0.0 D, even thought the C-O bonds are more polar
than S-O bonds. Explain this apparent contradiction.
11. Dimethyl sulfoxide ( DMSO ) has been used as an
anti-inflammatory rub for
race horses. DMSO and acetone seem to have similar structures, but the C=O
carbon atom in acetone is planar, while the S=O in DMSO is pyramidal. Draw
correct Lewis Structures for DMSO and acetone, predict the hybridizations and
explain these observations.
12. Rank the following species in order of increasing
basicity ( #1 least basic).
Explain your reasons for ordering them as you do.
___ CH3- ____ CH3COOH
13. N-Methylpyrrolidine has a boiling point of 81oC
and piperidine has a boiling
point of 106oC.
Tetrahydropyran has a boiling point of 53oC and cyclopentanol
boiling point of 141oC. These two isomers have a boiling point difference
of 53oC. Explain why the two oxygen-containing isomers have a much
larger boiling point difference than the amine isomers.
14. Draw the
Newman projection of trans-3-isobutyl-1-methylcyclohexane,
the two regular chair conformers and indicate which ( if any ) conformer is the
major conformer at equilibrium. Explain your answer.