CHEM 240: Survey of Organic Chemistry
at North Dakota State University
Midterm Exam 02 - Tue, 18 Oct 2016 - WHITE
!
Name:!
!
Please read through each question carefully and
answer in the spaces provided.
A good strategy is to go through the test and answer
all the questions you can do easily. Then go back and
tackle the more difficult problems.
Please make sure your structures are drawn clearly
and indicate any necessary stereochemistry with
bold/dashed bonds or proper conformational
drawings.
Finally, think about what you know. Common sense
and reason can often help you out.
Problem 1
8 pts
Problem 7
9 pts
Problem 2
12 pts
Problem 8
9 pts
Problem 3
10 pts
Problem 9
12 pts
Problem 4
14 pts
Problem 5
8 pts
Problem 6
18 pts
Chem 240 Midterm Exam 02!
BONUS
5 pts
TOTAL
100 pts
page 1!
fall 2016
1. Identify the relationship between the following pairs of molecules as Identical, Enantiomers or
Diastereomers. (check the appropriate box) (8 pts).
2. Determine the R or S configuration for the following molecules (check the appropriate box) (12 pts).
3. Answer TRUE or FALSE for each of the following questions about stereoisomers. (10 pts)
a) A meso compound has stereogenic centers.
b) A racemic mixture will rotate plane polarized light to the left.
c) Enantiomers are mirror image isomers that are not identical.
d) Cis-1,2-dimethylcyclopentate is chiral.
e) Proteins are chiral.
Chem 240 Midterm Exam 02!
page 2!
fall 2016
4. The acid-catalyzed addition of water to a double bond is shown below. The mechanism occurs over three
steps. Draw the structures of the intermediates 1 and 2 showing any charges (3 pts each). Draw curved
mechanism arrows for each step representing what is happening in the reaction (2 pts). Answer the following
questions about this reaction (2 pts each). (14 pts)
(a) Which of the following could possibly be a minor product of the reaction (circle it)?
(b) Which of the following reaction energy diagrams represents this reaction (circle it)?
(c) Which step is the Rate Determining Step of the reaction (circle it)?
1st step
2nd step
3rd step
5. For each of the following pairs of cations, circle the most stable one. (8 pts)
Chem 240 Midterm Exam 02!
page 3!
fall 2016
6. For each of the following reactions with 1,2-dimethylcyclohexene, draw the major organic product showing
all stereochemistry clearly with bold and dashed bonds where needed. (18 pts)
7. For each of the following multistep reactions, draw the major organic product. (9 pts)
Chem 240 Midterm Exam 02!
page 4!
fall 2016
8. Draw the structure for the following molecules showing stereochemistry clearly. (9 pts)
9. Each of the following reactions will produce two isomeric products. Draw the structures for the two isomers.
If the reaction would be expected to produce different amounts of the products, indicate the one that would the
major product (formed preferentially). What is their relationship (circle one)? (12 pts)
Chem 240 Midterm Exam 02!
page 5!
fall 2016
BONUS: The first resolution (separation) of enantiomers was done with a pair of tweezers and a magnifying
glass. Name the scientist that did this separation and name the chemical that was separated. (5 pts)
Chem 240 Midterm Exam 02!
page 6!
fall 2016