Organic Chemistry I Chem 334 - Fall 2010

Exam 1 Answer Key

Professor Carl C. Wamser

1.  (15 points)  Write complete names for each of the following. 

a) (CH3)2CH(CH2)3CHBrCH2Br

1,2-dibromo-6-methylheptane

b)

2-bromo-3-chloro-5-cyclohexyl-4-ethyl-2-methylhexane

c)

1-chloro-3-ethyl-2,3,5-trimethylhexane

2.  (15 points)  Write accurate structures for the following:

a)  a Newman diagram that shows the anti conformation of pentane

b)  the best conformation of trans-1,3-dimethylcyclohexane

c)  two good resonance forms for  HN3  (the three Ns are linear)
            (show all lone pairs and formal charges)

d)  1,2,6-trimethylbicyclo[4.2.0]octane

e)  1,2,6-trimethylspiro[2.5]octane

3.  (10 points)  Refer to the compound shown below.

What is its molecular formula?

C10 H13 N O

How many carbons are hybridized

sp   ______2_________

sp2  ______3_________

sp3  ______5_________

For each  sp3  carbon, identify its classification as 1°, 2°, 3°, or 4°.
Use arrows to specify each sp3 carbon on the structure above.

4.  (14 points)  Complete each of the following acid-base reactions.  Identify the pKa values of the acids on each side of the equation and predict the preferred direction of the equilibrium.

a)

b)

c)

d)

Of all the compounds cited above (on both sides of the equations), which is the strongest acid?

H2CO3

Which is the strongest base?

CH3-

5.  (18 points)  Write line structures and complete names for all of the isomers of formula  C5H10  that have one and only one ring.

6.  (12 points)  Complete the structures below by adding all the missing substituents at the appropriate places. 

a)

b)

7.  (16 points)  Write Newman diagrams for all three staggered conformations of  3-ethyl-2-methylpentane, looking down the C2-C3 bond.
Identify the relative energies of the three forms.

Write one Newman diagram of the same compound, looking down the C3-C4 bond.