Exam 2 Flashcards
1
Q
What type of isomers are CH3CH2OCH3 and CH3CH2CH2OH?
A) constitutional
B) symmetrical
C) configurational
D) conformational
E) stereochemical
A
A) constitutional
2
Q
A
A) Configurational isomers
3
Q
A
A) constitutional isomers
4
Q
A
B) constitutional isomers
5
Q
A
B) Constitutional isomers
6
Q
A
D) Configurational
7
Q
Which of the following cannot exhibit chirality?
A) 2, 3-dibromobutane
B) 1, 3-dibromobutane
C) 1, 2-dichlorobutane
D) 1, 4-dibromobutane
E) 1-bromo-2-chlorobutane
A
D) 1, 4-dibromobutane
8
Q
A
B
9
Q
A
achiral
10
Q
A
chiral
11
Q
A
achiral
12
Q
A
achiral
13
Q
A
A, B, and D
14
Q
A
III
15
Q
How many asymmetric centers are present in a molecule of 2,4,6-trimethylheptane?
A) 0
B) 1
C) 2
D) 3
E) 4
A
A) 0
16
Q
A
C) 3
17
Q
A
5
18
Q
A
D) configurational isomers
19
Q
A
C0 1
20
Q
A
C
21
Q
A and B are stereoisomers. They are nonsuperimposable and are mirror images of one another. Which of the following best describes the relationship between A and B?
A) structural isomers
B) enantiomers
C) conformational isomers
D) diastereomers
E) constitutional isomers
A
B) enantiomers
22
Q
A
D) identical compounds
23
Q
A
E) It does not have an enantiomer.
24
Q
A
D) The mirror image of this molecule is its enantiomer.
25
E
26
the same compound
27
D) S, S, S
28
C) B and D
29
B) A and C
30
B
31
A
32
D) —O—CH3
33
A) R configuration
34
35
A) R, S, R
36
L-amino acid
37
D-sugar
38
III
39
In the boat conformation of cyclohexane, the "flagpole" hydrogens are located on \_\_\_\_\_\_\_\_.
A) the same carbon
B) adjacent carbons
C) C-1 and C-3
D) C-1 and C-4
E) none of the above
D) C-1 and C-4
40
Which conformer is at a local energy minimum on the potential energy diagram in the chair-chair interconversion of cyclohexane?
A) half-chair
B) planar
C) boat
D) twist-boat
E) fully eclipsed
D) twist-boat
41
D) cis-1,3-dichlorocyclohexane
42
Which of the following has two equatorial alkyl substituents in its most stable conformation?
A) 1,1-dimethylcyclohexane
B) cis-1,2-dimethylcyclohexane
C) cis-1,3-diethylcyclohexane
D) cis-1,4-diethylcyclohexane
E) trans-1,3-diethylcyclohexane
C) cis-1,3-diethylcyclohexane
43
Identify the compound where the groups are axial and equatorial.
A) trans-1,4-dibromocyclohexane
B) cis-1,4-dibromocyclohexane
C) cis-1,3-dibromocyclohexane
D) trans-1,2-dibromocyclohexane
E) none of them
B) cis-1,4-dibromocyclohexane
44
Identify the least stable conformation for 1-tert-butyl-3-methylcyclohexane.
A) tert-butyl is axial and the methyl is equatorial.
B) tert-butyl is axial and the methyl is axial.
C) tert-butyl is equatorial and the methyl is axial.
D) tert-butyl is equatorial and the methyl is equatorial.
E) All are equally stable.
B) tert-butyl is axial and the methyl is axial.
45
How many constitutional isomers are possible for C6H14?
A) 4
B) 5
C) 6
D) 7
E) 8
B) 5
46
If an acyclic alkane hydrocarbon contains n carbon atoms, how many hydrogen atoms must it also contain?
A) n
B) n + 2
C) n - 2
D) 2n
E) 2n + 2
E) 2n + 2
47
Which of the following is a true statement?
A) All chiral molecules possess a plane of symmetry.
B) All achiral molecules are meso.
C) All molecules which possess a single chirality center of the S configuration are levorotatory.
D) A mixture of achiral compounds will be optically inactive.
E) All molecules which possess two or more chirality centers will be chiral
D) A mixture of achiral compounds will be optically inactive.
48
Which of the following is not true of enantiomers?
A) They have the same melting point.
B) They have the same boiling point.
C) They have the same chemical reactivity with non-chiral reagents.
D) They have the same density.
E) They have the same specific rotation.
E) They have the same specific rotation.
49
Which of the following is/are optically inactive?
A) a 50-50 mixture of R and S enantiomers
B) a meso compound
C) every achiral compound
D) a racemic mixture
E) all the above
E) all the above
50
Which of the following statements correctly pertains to a pair of enantiomers?
A) They rotate the plane of polarized light by exactly the same amount and in opposite directions.
B) They rotate the plane of polarized light by differing amounts and in opposite directions.
C) They rotate the plane of polarized light by differing amounts and in the same direction.
D) They have different melting points.
E) They have the same melting point, but they have different boiling points.
A) They rotate the plane of polarized light by exactly the same amount and in opposite directions.
51
A mixture of equal amounts of two enantiomers \_\_\_\_\_\_\_\_.
A) is called a racemic mixture
B) is optically inactive
C) implies that the enantiomers are meso forms
D) both A and B
E) none of the above
D) both A and B
52
E) enantiomers
53
B) diastereomers
54
A) enantiomers
55
B) diastereomers
56
Which of the following is chiral?
A) cis-1-bromo-3-chlorocyclobutane
B) trans-1-bromo-3-chlorocyclobutane
C) cis-1,4-dimethylcyclohexane
D) cis-1,3-dimethylcyclohexane
E) trans-1,3-dimethylcyclohexane
E) trans-1,3-dimethylcyclohexane
57
C) 6
58
Enantiomers
59
Diatereomers
60
Diastereomers
61
Steroisomers which are not mirror image isomers are \_\_\_\_\_\_\_\_
diatereomers
62
the same compound
63
the same compound
64
enantiomers
65
D) A and B, A and D, B and C, C and D
66
B) A and C
67
E) B and D, A and B, A and D, B and C, C and D
68
A
69
E) identical compounds
70
Which of the following is a meso compound?
A) trans-1, 4-dimethylcyclohexane
B) cis-1, 3-dimethylcyclohexane
C) trans-1, 3-dimethylcyclohexane
D) cis-1, 4-dimethylcyclohexane
E) trans-1, 2-dimethylcyclohexane
B) cis-1, 3-dimethylcyclohexane
71
How many stereoisomers exist with the following basic connectivity?
BrCH2CH(CH3)CH2CH3
A) 0
B) 1
C) 2
D) 4
E) 8
C) 2
72
How many stereoisomers exist with the following basic connectivity?
CH3CHClCH2CHClCH3
A) 0
B) 1
C) 2
D) 3
E) 4
D) 3
73
Which of the statements below correctly describes an achiral molecule?
A) The molecule has a nonsuperimposable mirror image.
B) The molecule exhibits optical activity when it interacts with plane-polarized light.
C) The molecule has an enantiomer.
D) The molecule might be a meso form.
E) none of the above
D) The molecule might be a meso form.
74
achiral
75
Chiral
76
achiral
77
chiral
78
C) 2S, 3S
79
A) 2R, 3R
80
Answer: E
81
C) constitutional isomers
82
Give the general formula for a cyclic alkene.
A) CnH2n-4
B) CnH2n-2
C) CnH2n
D) CnH2n+2
E) CnH2n+2
B) CnH2n-2
83
Give the possibilities in structure for a compound with a formula of C6H10.
A) no rings, no double bonds, no triple bonds
B) one double bond, or one ring
C) two rings, two double bonds, one double bond + one ring, or one triple bond
D) three rings, three double bonds, two double bonds + one ring, one ring + two double bonds, one triple bond + one ring, or one double bond + one ring
E) benzene
C) two rings, two double bonds, one double bond + one ring, or one triple bond
84
Give the degree of unsaturation for benzene.
A) 1
B) 2
C) 3
D) 4
E) 5
D) 4
85
β-Phellandrene is a hydrocarbon component of eucalyptus oil whose molecular formula is A molecule of β-phellandrene contains 2 π-bonds. How many rings are in β-phellandrene?
A) 0
B) 1
C) 2
D) 3
E) 4
B) 1
86
A hydrocarbon with molecular formula C20H34 has what degree of substitution?
A) 2
B) 3
C) 4
D) 5
E) 6
C) 4
87
Muscalure, the sex attractant of the common housefly, is an acyclic alkene that contains 23 carbons. How many hydrogen atoms are in a molecule of muscalure
46
88
A) 2-ethyl-1-pentene
89
E) 2-methyl-1,4-pentadiene
90
A) 7-chloro-3-ethyl-4-methyl-3-heptene
91
Identify the true statements in the mechanism in the addition of water to an alkene.
A) The addition of the electrophile is a slow step.
B) The addition of the nucleophile is a fast step.
C) A carbocation is formed as an intermediate.
D) Water abstracts the extra proton from the protonated alcohol.
E) All of the above
E) All of the above
92
D) all of them
93
E) II and IV
94
C) 2,3-dimethyl-2-butanol
95
C
96
Which of the following is the best reaction sequence to use if one wants to accomplish a Markovnikov addition of water to an alkene with minimal skeletal rearrangement?
A) water + dilute acid
B) water + concentrated acid
C) oxymercuration-demercuration
D) hydroboration-oxidation
E) none of the above
C) oxymercuration-demercuration
97
B) II
98
D) IV
99
Give the product for the reaction that occurs when 1-pentene is treated with Cl2.
A) 1-chloropentane
B) 2-chloropentane
C) 1,1-dichloropentane
D) 2,2-dichloropentane
E) 1,2-dichloropentane
E) 1,2-dichloropentane
100
Give the intermediate for the halohydrin reaction.
A) a halonium ion
B) the most stable carbocation with OH on the adjacent carbon
C) the most stable carbocation with X on the adjacent carbon
D) a cyclic oxonium ion
E) the most stable carbanion
A) a halonium ion
101
Which of the following reagents gives the reaction shown below?
CH3CH= CH2 + ? → CH3CH2CH3
A) H2/HCl
B) H2/H2SO4
C) H2/Ni
D) H2O/Ni
E) H2O/H2SO4
C) H2/Ni
102
What is the product of the hydrogenation of an alkene?
A) dihaloalkane
B) alkane
C) haloalkane
D) alcohol
E) ether
B) alkane
103
Upon hydrogenation, which of the following alkenes releases the least heat per mole?
A) 3,4-dimethyl-1-hexene
B) (Z)-3,4-dimethyl-2-hexene
C) (E)-3,4-dimethyl-2-hexene
D) (Z)-3,4-dimethyl-3-hexene
E) (E)-3,4-dimethyl-3-hexene
E) (E)-3,4-dimethyl-3-hexene
104
Identify the products of cis-3-methyl-3-hexene with hydrogen bromide.
A) (2R, 3S)-3-bromo-3-methylhexane
B) (2R, 3R)-3-bromo-3-methylhexane
C) (2S, 3R)-3-bromo-3-methylhexane
D) (2S, 3S)-3-bromo-3-methylhexane
E) All of the above answers
E) All of the above answers
105
