CH 201
Exam #2
October 15, 1997

Name ______________________________

ΔGo= ΔHo- T ΔSo

Page

Points

1

______(18)

ΔGo= -R T ln K

2

______(18)

R = 8.314 Joule/mole-K and 0oC = 273K

3

______(17)

4

______(17)

5

______(14)

6

______(16)

Total

________

1. (a)Provide IUPAC names for the following molecules.
Don't forgetto indicate stereochemistrywhen applicable (i.e cis or trans). (9 pts)

H3C

C

CH3

CH3

CH

CH2

CH2

CH2

CH3

Br

H

H

H

CH2CH3

H

__________________________

____________________________

_____________________

(b) (9 pts) Provide structures for the following molecules.

cis-1,2-Dimethylcyclopentane

tert-butylcyclopentane

isopropyl bromide

1

2. (15 pts)Consider the energy diagram shown below for the reactionA + B ----->C + D :

4

6

8

10

12

14

16

2

energy
(kJ/mol)

A + B

C + D

progress of reaction

a. What is the value of ΔH for the reactionC + D→A+B? (Give the number and sign.)_________

b. What is the value of Eafor the reactionA + B

→C + D? (Give the number and sign.) __________

c. Is the reactionC + D→A+Bendothermicor exothermic?____________________

d. What is the value of Eafor the reactionC + D

→A+B? (Give the number and sign.)__________

e. According to the Hammond Postulate, should the transition state for the reactionA + B→C + D
resemble A and B or should it resemble C and D?

3. Circle the strongest Lewis base and explain why it is. (3 pts)

N

N

2

4. Consider the reaction below:

CH3O-

+NH3----------->NH2-+CH3OH

a. (4 pts)Given that the pKafor NH3is 36 and the pKafor CH3OH is 16, does the reaction lie to the left
or the right as written? ____________ Calculate the value of Keqfor the reaction as it is written above.

b. (6 pts)Write the two chemical equations that, when added, give the equation above and allow you to
do the Keqcalculation.

5. (7pts) Using the table of bond dissociation energies on the first page, calculate the ΔHºrxnfor the
following reaction.

C

C

H

H

+2 H2

H3C

CH3

YOU MUST SHOW YOUR WORK IN DETAIL IN ORDER TO RECEIVE CREDIT.

3