CH 201
Exam #2
October 20, 2000

Name ______________________________

Page

Points

1

______(06)

ΔGo= ΔHo- T ΔSo

2

______(12)

ΔGo= -R T ln K(R = 0.008317 KJ mole-1degK-1)

3

______(24)

Table of Acidities

4

______(15)

Acid

pKa

5

______(18)

CH3CH2OH

17

6

______(12)

H2O

16

7

______(13)

CH3COOH

5

Total

______(100)

HCl

-7

HBr

-9

1. (a)Provide IUPAC names for the following molecules. Don't forget to indicatestereochemistrywhen
applicable (i.e R or S, cis or trans). (6 pts)

CH3

HO

H

CH2CH3

Cl

H3C

CH2CH2CH3

Cl

CH3

H3C

1

(b)Provide IUPAC names for the following molecules. Don't forget to indicate stereochemistry when
applicable (i.e R or S, cis or trans). (6 pts)

H3C

CH3

CH3

CH3

CH3
CH3

H2C

OH

CH3

H3C

H3C

CH3

(c) (4 pts) Provide structures for the following molecules.

cis-1,2-Dimethylcyclopropane

2,4,4-trimethyl-2-pentene

(d) Which of the following molecules is [3.2.1]bicyclooctane? (please circle). (2pts)

2

2. (a) (7 pts) Draw the two chair conformations for cis-1,3,5-trimethylcyclohexane (all 3 methyls are cis)
showing all bonds to the cyclohexane carbons explicitly and label the methyl substituents as axial or
equatorial (methyls may be written as CH3). (clarity counts!)Circle the most stable conformer.

H3C

(b)If each methyl in an axial position is worth 7.6 KJ of torsional strain energy what is the energy
difference (ΔG) between the two isomers in part a? (2 pts)

(c) What is the equilibrium constant K between the conformational isomers at 2980K? (3 pts)

3. Draw Newman projections for all the conformational isomers for 2-methylbutane looking down the C2-
C3 bond. (neatness and clarity count!) (Hint: there are 4 of them, 2 staggered and 2 ecclipsed) (8 pts)

(b) In your diagrams above labelthemost stableand least stableconformer . (4 pts)

3