Chemistry 2411
Dr. Sheppard
Assignment 3: 20 points
Due March 26, 2015
1. Name the following alkene.
A. trans-2-pentene
B. cis-2-pentene
C. E-3-methyl-2-pentene
D. Z-3-methyl-2-pentene
E. cis-2-ethyl-2-butene
Name ________________________________
CH3
CH3
C
C
H
CH2CH3
2. Choose the most stable alkene among the following:
A. 1-hexene
B. (E)-2-hexene
C. (Z)-2-hexene
D. They are all of equal stability.
OCH3
3. Which of the following best describes the geometry about
the carbon-carbon double bond in this alkene?
A. E
B. Z
C. neither E nor Z
OH
Br
4. Which has one chiral center?
A. 1-chloropropane
B. 2-chloropropane
C. 3-chloropentane
D. 2-chloropentane
5. Which cyclobutane is chiral?
A. trans-1,2-dimethylcyclobutane
B. cis-1,3-dimethylcyclobutane
C. 1,1-dimethylcyclobutane
D. cis-1,2-dimethylcyclobutane
6. Which substituent has the highest priority?
A. -CH2OH
B. -CHO
C. -CH2CH2OH
D. -CH2OCH3
7. With regard to the priority rules, which one of the following statements is correct?
A. -CCl(CH3)2 < -CH2-CHCl-CH3
B. -Cl > -Br
C. -CH(CH2Cl)2 < -CCl2-CHCl-CH3
D. -CH(CH3)2 < -CH2-CH2-CH3
E. -H > -D
8. How many asymmetric carbon atoms are
present in the following compound?
A. 0
B. 1
C. 2
D. 3
E. 4
CH3
CH3
CH(CH3)2
Chemistry 2411
Dr. Sheppard
Assignment 3: 20 points
Due March 26, 2015
Name ________________________________
9. What is the relation between an enantiomer's configuration and its specific rotation?
A. R compounds usually are dextrorotatory with few exceptions.
B. R compounds always are dextrorotatory.
C. There is no relation.
D. R compounds always are levorotatory.
10. This molecule is:
A. R
B. S
C. Achiral
D. Cannot be determined
11. This molecule is:
A. R
B. S
C. Achiral
D. Cannot be determined
12. This molecule is:
A. R
B. S
C. Achiral
D. Cannot be determined
CH3
Br
Cl
H
CH2CH2CH3
CH3
CH3CH2
CH
CH3
CH3
CH3
CH2CH3
13. What is the maximum number of stereoisomers for a compound with n chiral centers?
A. n2
B. 2n
C. 2n
D. 22n
14. How many stereoisomers of 1-bromo-2-chloroheptane can exist?
A. 2: a pair of enantiomers
B. 5: two pairs of enantiomers and a meso form
C. 4: two pairs of enantiomers
D. 3: one pair of enantiomers and a meso form
15. With two chiral centers present, we can realize stereoisomers that are (R,R), (S,S), (S,R),
and (R,S). Which represents a pair of diastereomers?
A. (R,S) and (S,R)
B. (R,R) and (S,S)
C. (S,R) and (R,S)
D. (S,S) and (R,S)
16. Which of the following molecules is different?
A.
B.
C.
D.
Chemistry 2411
Dr. Sheppard
Assignment 3: 20 points
Due March 26, 2015
Name ________________________________
17. What is the IUPAC name of this compound?
A. (1S,3S)-1,3-dichloro-1-ethyl-3-methylcyclopentane
B. (1R,3S)-1,3-dichloro-1-methyl-3-ethylcyclopentane
C. (1R,4S)-1,4-dichloro-1-ethyl-4-methylcyclopentane
D. (1R,3S)-1,3-dichloro-1-ethyl-3-methylcyclopentane
E. (1S,3R)-1,3-dichloro-3-ethyl-1-methylcyclopentane
Cl
Cl
CH3
CH2CH3
18. Enantiomers have
A. Different physical properties
B. Same physical properties.
C. This cannot be predicted
19. (2S,3S)-2,3-dichloropentane and (2R,3R)-2,3-dichloropentane are:
A. Enantiomers
B. Diastereomers
C. Constitutional isomers
D. Different conformations of the same compound
20. How many chiral centers are there in tartaric acid, and
how many different stereoisomers exist for this acid?
A. 2 chiral centers; 2 isomers
B. 1 chiral center; 1 isomer
C. 2 chiral centers; 4 isomers
D. 2 chiral centers; 3 isomers
OH
O
HO
OH
O
OH
tartaric acid
21. Which best defines a meso compound?
A. a molecule with a plane of symmetry and no chiral center
B. a molecule that can be superposed on its mirror image and that does contain chiral centers
C. a molecule that cannot be superposed on its mirror image even though it has no chiral centers
D. a molecule that has no mirror image
22. Which of the following is optically active?
A. A chiral compound
B. An achiral compound
C. A racemic mixture
D. A meso compound
E. All of these are optically active
23. Identify the number of stereoisomers for 3-bromo-2,4,5-trichlorohexane.
A. 8
B. 12
C. 16
D. 24
24. Diastereomers have
A. Different physical properties
B. Same physical properties.
C. This cannot be predicted
25. Bromobenzene is chiral.
A. True
B. False
Chemistry 2411
Dr. Sheppard
Assignment 3: 20 points
Due March 26, 2015
Name ________________________________
26. The two structures shown here are:
A. the same compound
B. enantiomers
C. diastereomers
D. constitutional isomers
Use the following four structures to answer questions 27-29 below.
27. Which are diastereomers?
A. I and IV
B. I and II
C. II and III
D. None of these are diastereomers
28. Which are enantiomers?
A. I and IV
B. I and II
C. II and III
D. I and III
29. Which is a meso compound?
A. I
B. II
C. III
D. I and IV
30. Rankeach of the following groups of substituents in order of priority from highest (1) to lowest (4).
(a) –CHO
–CH=CH–CH3
–CH=N–CH3
–CO2H
(b) –C≡C–H
–NHC(O)CH3
–CH(CH3)OH
–CH(CH3)2
31. Circle all the following structures that have a plane of symmetry.
Chemistry 2411
Dr. Sheppard
Assignment 3: 20 points
Due March 26, 2015
Name ________________________________
32. (a) Draw the Fischer projection for (2R,3S)-2,3-dibromobutane.
(b) Is (2R,3S)-2,3-dibromobutane geminal or vicinal? ______________
(c) Is (2R,3S)-2,3-dibromobutane optically active? ______________
33. Determine whether the two structures in each of the following pairs represent constitutional
isomers, enantiomers, diastereomers, or identical compounds.
(a)
(b)
(c)
(d)
(e)
(S)-1-ethyl-1,2,2-trimethylcyclopropane