Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) W hich of the follow ing is a tertiary amine?
1)
A)
B)
C)
D)
E)
Answ er: B
2) There are 8 isomers that have the molecular formula C5 H11 Br. How many of these are tertiary
2)
alkyl bromides?
A) 2
B) 8
C) 3
D) 1
E) 0
Answ er: D
3) W hich of the follow ing is sec-butyl alcohol?
3)
A) (CH3 )2 CHOH
B) CH3 CH(OH)CH2 CH3
C) CH3 CH2 CH2 CH2 OH
D) (CH3 )2 CHOCH3
E) (CH3 )2 CHCH2 OH
Answ er: B
1
4) W hat is the common name for the follow ing structure?
4)
A) Isopropylmethane
B) n-Butane
C) t-Butane
D) Isobutane
E) sec-Butane
Answ er: D
5) Give the IUPAC name for the follow ing structure:
5)
A) 5-Isopropyloctane
B) 4-Isopropyloctane
C) 3-ethyl-2-methylheptane
D) 2-methyl-3-propylheptane
E) 2-methyl-3-ethylheptane
Answ er: B
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
6) There is something w rong w ith the follow ing name. W rite the structure and cor rect the
6)
name: 2-ethylpropane.
Answ er:
The cor rect name is 2-methylbutane.
7) Give structures for the three isomers w ith molecular for mula C5 H12 and provide the
common name of each.
Answ er:
2
7)
8) Provide an acceptable name for the alkane show n below .
8)
CH3 CH2 CH2 CH2 CH2 CH3
Answ er: hexane or n-hexane
9) Provide an acceptable name for the alkane show n below .
9)
Answ er: 2, 5-dimethylheptane
10) Provide an acceptable name for the alkane show n below .
10)
Answ er: 5-sec-butyl-2, 2-dimethylnonane or
2, 2-dimethyl-5-(1-methylpropyl) nonane
11) Provide an acceptable name for the alkane show n below .
11)
Answ er: 4-isopropyldecane or 4-(1-methlyethyl) decane
12) Provide an acceptable name for the alkane show n below .
Answ er: 3-ethyl-6-methyl-5-propylnonane
3
12)
13) Provide an acceptable name for the alkane show n below .
13)
Answ er: 3-ethyl-4, 4-dimethylheptane
14) Draw an acceptable structure for 4-t-butyloctane.
14)
Answ er:
15) Draw an acceptable structure for 3-ethyl-3-methylhexane.
15)
Answ er:
16) Draw an acceptable structure for 4-isopropyl-2-methylheptane.
16)
Answ er:
17) Draw an acceptable structure for 6-ethyl-2, 6, 7-trimethyl-5-propylnonane.
Answ er:
4
17)
18) Provide an acceptable name for the alkane show n below .
18)
Answ er: 2, 2, 3, 6-tetramethylheptane
19) Provide an acceptable name for the alkane show n below .
19)
Answ er: 6-ethyl-2-methyl-5-propyldecane
20) Give the systematic name of the alkane show n below .
20)
Answ er: 4-ethyl-2,2,7-trimethylnonane
21) Give the systematic name of the alkane show n below .
Answ er: 3-ethyl-4-isopropyloctane
5
21)
22) Give the systematic name of the cycloalkane show n below .
22)
Answ er: 4-butyl-1,2-dimethylcyclohexane
23) Draw an acceptable structure for sec-butylcyclopentane.
23)
Answ er:
24) Provide the systematic name of the compound show n.
24)
Answ er: 4-butyl-1-ethyl-2-methylcycloheptane
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
25) W hat is the common name for the follow ing structure?
A) sec-Butyl b romide
B) Isobutyl bromide
C) Neobutyl bromide
D) Isopropyl methyl bromide
E) t-Butyl b romide
Answ er: E
6
25)
26) Give the IUPAC name for the follow ing compound:
26)
A) 1-methyl-5-chlorocyclohexane
B) 1-chloro-5-methylcyclohexane
C) 1-methyl-2-chlorocyclohexane
D) 1-chloro-2-methylcyclohexane
E) 1, 2-chloromethylcyclohexane
Answ er: D
27) W hich of the follow ing is diisopropyl ether?
27)
A)
B) (CH3 )2 CH)CH(CH3 )2
C) (CH3 )3 COC(CH3 )3
D) CH3 CH2 CH2
O
CH2 CH2 CH3
E) CH3 CH2 CH2 OCH(CH3 )2
Answ er: B
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
28) Draw all ethers w ith molecular for mula C4 H10 O.
28)
Answ er:
29) Draw all possible constitutional isomers for C2 H6 O and give common names for each
structure.
Answ er:
7
29)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
30) Give the IUPAC name for the follow ing structure:
30)
A) 2-methyl-3-chlorocyclohexanol
B) 3-chloro-2-methylcyclohexanol
C) 2-methyl-5-chlorocyclohexanol
D) 5-chloro-2-methylcyclohexanol
E) 1-chloro-4-methylcyclohexanol
Answ er: D
31) W hich of the follow ing compounds does not have the molecular for mula C6 H14 O?
31)
A) 3-methyl-3-pentanol
B) 2-hexanol
C) cyclohexanol
D) 1-hexanol
E) 3-methyl-2-pentanol
Answ er: C
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
32) Give the structure of isopentyl alcohol.
32)
Answ er:
33) Provide the systematic name of the compound show n.
Answ er: 6,7-dimethyl-3-octanol
8
33)
34)
34) Draw the structure of 3-chloro-N-ethyl-2-hexanamine.
Answ er:
35) Give the structure of tetramethylammonium chlor ide.
35)
Answ er:
36) Draw the structure of N-ethyl-5-methyl-3-hexanamine.
36)
Answ er:
37) Fluor ine is mor e electronegative than chlor ine yet the carbon -fluor ine bond in CH3 -F is
37)
shorter than CH3 -Cl. Explain.
Answ er: Chlor ine is a larger atom than fluor ine and uses a 3p rather than 2p or bital. The
overlap of a 2sp3 or bital w ith a 3p or bital is not as good as the overlap of a 2sp 3
or bital w ith a 2p or bital, causing the bond to b e longer and w eaker.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
38) W hich of the follow ing w ill have the low est boiling point?
A) CH4
B) CCl4
C) CH2 Cl2
38)
D) CHCl3
E) CH3 Cl
Answ er: A
39) W hich of the compounds below w ill form hydrogen bonds betw een its molecules?
A) CH3 CH2 CH2 CH3
l
j
B) (CH3 )3 N
C) CH3 CH2 CH2 F
D) CH3 NHCH2 CH3
E) CH3 CH2 OCH3
Answ er: D
9
39)
40) W hich of the follow ing has the greatest van der W aal's interaction betw een molecules of the
40)
same kind?
A) CH3 CH2 CH2 CH3
B)
C)
D)
E) CH3 CH2 CH2 CH2 CH3
Answ er: E
41) W hich of the follow ing has the low est boiling point?
41)
A) CH3 CH2 CH2 CH2 CH2 CH3
B)
C) CH3 CH2 CH2 CH2 CH2 CH2 CH3
D)
E)
Answ er: E
42) W hich of the follow ing has the greatest solubility in CH3 CH2 CH2 CH3 ?
A) CH3 NH2
B) CH3 OCH3
C) CH3 O- Na +
D) (CH3 )3 CH
E) CH3 OH
Answ er: D
10
42)
43) W hich of the follow ing is the most soluble in H2 O?
43)
A) CH3 CHO
B) CH3 CH2 OH
C) CH3 OCH3
D) CH3 CH2 Cl
E) CH3 CH2 CH3
Answ er: B
44) W hich of the follow ing w ould have the highest boiling point?
A) CH3
O
CH2 CH2 CH2
B) CH3 CH2
C) HO
O
CH2 CH2
CH2 CH2 CH2 CH2
O
CH3
O
CH3
44)
OH
D)
E) CH3 CH2
O
CH2
O
CH2 CH3
Answ er: C
45) Consider the three isomeric alkanes n-hexane, 2, 3-dimethylbutane, and 2-methylpentane.
45)
W hich of the follow ing correctly lists these compounds in order of increasing boiling point?
A) 2-methylpentane < n-hexane < 2, 3-dimethylbutane
B) 2, 3-dimethylbutane < 2-methylpentane < n-hexane
C) 2-methylpentane < 2, 3-dimethylbutane < n-hexane
D) n-hexane < 2, 3-dimethylbutane < 2-methylpentane
E) n-hexane < 2-methylpentane < 2, 3-dimethylbutane
Answ er: B
46) W hat is the strongest intermolecular force present in liquid ethanol?
46)
A) dipole-dipole, but not hydrogen bonding
B) induced dipole-induced dipole
C) ion-ion
D) dipole-dipole, specifically hydrogen bonding
E) ion-dipole
Answ er: D
47) Assuming roughly equivalent molecular w eights, w hich of the follow ing w ould have the
highest boiling point?
A) a quaternary ammonium salt
B) an alcohol
C) an alkyl chloride
D) a tertiary amine
E) an ether
Answ er: A
11
47)
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
48) Explain w hy
has a low er boiling point than CH3 CH2 CH2 CH3 .
48)
Answ er: CH3 CH2 CH2 CH3 has greater van der W aals forces because it has a greater
contact area than isob utane. Therefor e, the boiling point of CH3 CH2 CH2 CH3 is
higher.
49) Primary and secondary amines exhibit hydrogen bonding; tertiary amines do not.
49)
Explain.
Answ er: The nitrogen in a tertiary amine is not attached to a hydrogen. Recall that for a
molecule to exhibit hydrogen bonding it must have a hydrogen attached to a
highly electronegative atom such as F, N, or O.
50) Explain w hy trimethylamine, (CH3 )3 N:, has a considerably low er boiling point than
50)
propylamine CH3 CH2 CH2 NH2 , even though both compounds have the same molecular
formula.
Answ er: Since hydrogen bonding is possible for propylamine and not for trimethylamine,
the boiling point is higher for propylamine.
51) W hich of the molecules below has the higher boiling point? Briefly explain your choice.
CH3 CH2 CH2 OH
or
51)
CH3 CH2 OCH3
Answ er: CH3 CH2 CH2 OH has the higher boiling point since it is capable of intermolecular
hydrogen bonding.
52) W ould you expect sodium chlor ide (NaCl) to b e highly soluble in the or ganic solvent
52)
hexane (CH3 CH2 CH2 CH2 CH2 CH3 )? Briefly explain your answ er.
Answ er: One w ould not expect NaCl to b e highly soluble in hexane. NaCl is an ionic solid
(i.e., a very polar material) w hile hexane is nonpolar. Nonpolar solvent
molecules do not solvate ions w ell. The attractions of oppositely charged ions to
each other are vastly greater than the w eak attractions of the ions for the
solvent.
53) W hich compound is more soluble in w ater? Briefly explain your choice.
CH3 OCH3
or
53)
CH3 CH2 OH
Answ er: CH3 CH2 OH is mor e soluble in w ater since it can donate a hydrogen bond to
w ater and accept a hydrogen bond from w ater. CH3 OCH3 can only accept a
hydrogen bond from w ater; it has no hydrogen w hich can hydrogen bond to
w ater.
54) W hich compound is more soluble in w ater? Briefly explain your choice.
(CH3 )2 NH
or
CH3 CH2 CH3
Answ er: (CH3 )2 NH is mor e soluble in w ater since it can hydrogen bond w ith w ater.
Alkanes are not capable of hydrogen bonding w ith w ater.
12
54)
55) W hich intermolecular force is primarily responsible for the interactions among alkane
55)
molecules?
Answ er: Van der W aal's or London forces
56)
56) W hat is polarizability and how is it related to the size of an atom?
Answ er: Polarizability indicates the ease w ith w hich an electron cloud can be distorted.
The larger the atom, the mor e loosely its nucleus holds the electrons in its
outermost shell, and the mor e they can be distor ted.
57) Ar range the follow ing amines in or der of increasing boiling point, low est bp to highest
57)
bp: (CH3 )2 CHCH2 CH2 NH2 , (CH3 )2 CHN(CH3 )2 , and (CH3 )2 CHCH2 NHCH3 .
Answ er: (CH3 )2 CHN(CH3 )2 < (CH3 )2 CHCH2 NHCH3 < (CH3 )2 CHCH2 CH2 NH2
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
58) The eclipsed and staggered forms of ethane are said to differ in:
58)
A) configuration.
B) conformation.
C) constitution.
D) molecular formula.
E) structure.
Answ er: B
59) W hich of the follow ing is the stagger ed confor mation for rotation about the C 1
C2 bond in the
follow ing structure?
A) I
B) II
C) III
D) IV
Answ er: A
13
E) V
59)
60) Among the butane conformers, w hich occur at energy minima on a graph of potential energy
60)
versus dihedral angle?
A) gauche and anti
B) anti only
C) eclipsed only
D) eclipsed and totally eclipsed
E) gauche only
Answ er: A
61) W hich of the follow ing best explains the relative stabilities of the eclipsed and staggered forms
61)
of ethane? The __________ form has the most __________ strain.
A) eclipsed; torsional
B) eclipsed; steric
C) staggered; tor sional
D) staggered; steric
Answ er: A
62) W hich of the follow ing best explains the reason for the relative stabilities of the conformers
62)
show n?
A) II has mor e steric strain.
B) I has mor e steric strain.
C) I has mor e tor sional strain.
D) II has mor e tor sional strain.
Answ er: A
63) W hich of the follow ing statements about the conformers that result from rotation about the
C2-C3 bond of butane is cor rect?
A) Tor sional strain is absent in the eclipsed for ms.
B) The gauche conformer is an eclipsed one.
C) Steric strain is absent in the eclipsed for ms.
D) The highest energy conformer is one in w hich methyl groups are eclipsed by hydrogens.
E) none of the above
Answ er: E
14
63)
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
64) Draw the New man proj ection that represents the most stable confor mation of
64)
3,3-dimethylhexane view ed along the C3-C4 bond.
Answ er:
65) Draw the New man proj ection that represents the least stable confor mation of
65)
3,3-dimethylhexane view ed along the C3-C4 bond.
Answ er:
66) Draw the New man structure for the most stable confor mation of 1 -bromopropane
66)
considering rotation about the C1 -C2 bond.
Answ er:
67) Draw a New man proj ection of the most stable confor mation of 2 -methylpropane.
67)
Answ er:
68) Define the term conformation.
68)
Answ er: Conformations are different arrangements of the same molecule for med by
rotations about single bonds.
15
69) Use a saw hor se structure to depict the eclipsed conformer of ethane.
69)
Answ er:
70) View a butane molecule along the C2 -C3 bond and provide a New man proj ection of the
70)
low est energy conformer.
Answ er:
71) Provide a representation of the gauche confor mer of butane.
71)
Answ er:
72) Draw the New man proj ection of the most stable confor mation that results due to
rotation about the C2 -C3 bond in 2,3-dimethylbutane.
Answ er:
16
72)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
73) W hich of the follow ing cor rectly ranks the cycloalkanes in or der of increasing ring strain per
73)
methylene?
A) cyclopropane < cyclobutane < cyclohexane < cycloheptane
B) cyclopentane < cyclopropane < cyclobutane < cyclohexane
C) cyclohexane < cyclopentane < cyclobutane < cyclopropane
D) cyclopropane < cyclopentane < cyclobutane < cyclohexane
E) cyclopentane < cyclobutane < cyclopentane < cyclopropane
Answ er: C
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
74)
74) Describe the source of angle strain and tor sional strain present in cyclopropane.
Answ er: The angle strain arises from the compression of the ideal tetrahedral bond angle
of 109.5° to 60°. The large tor sional strain occurs since all C-H bonds on adj acent
carbons are eclipsed.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
75) W hich of the follow ing cor rectly lists the confor mations of cyclohexane in or der of increasing
75)
energy?
A) half-chair < tw ist-boat < boat < chair
B) chair < boat < tw ist-boat < half-chair
C) half-chair < boat < tw ist-boat < chair
D) chair < tw ist-boat < half-chair < boat
E) chair < tw ist-boat < boat < half-chair
Answ er: E
76) W hich of the follow ing is the most stable conformation of bromocyclohexane?
A) I
B) II
C) III
D) IV
Answ er: C
17
76)
E) V
77) In the boat conformation of cyclohexane, the "flagpole" hydrogens are located:
77)
A) on C-1 and C-4.
B) on C-1 and C-3.
C) on adj acent carbons.
D) on the same car bon.
E) none of the above
Answ er: A
78) W hich confor mer is at a local energy minimum on the potential energy diagram in the
78)
chair-chair interconversion of cyclohexane?
A) boat
B) planar
C) fully eclipsed
D) tw ist-boat
E) half-chair
Answ er: D
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
79) Draw the chair confor mer of cyclohexane. Label the axial hydrogens (Ha ) and the
79)
equator ial hydrogens (He).
Answ er:
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
80) The Keq for the interconversion for the tw o chair for ms of methylcyclohexane at 25 °C is 18.
W hat % of the chair conformers feature an axial methyl group?
A) 5
B) 75
C) 25
D) 95
E) 50
Answ er: A
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
81) The equilibrium constant for the ring-flip of fluor ocyclohexane is 1.5 at 25 °C. Calculate
the percentage of the axial conformer at the temperature.
Answ er: Keq =
[eq]
[ax]
% axial =
=
= 1.5
[ax]
[eq] +[ax]
[1]
[1.5] + [1]
100%
100%
= 40%
18
81)
80)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
82) W hich of the follow ing describes the most stable confor mation of
82)
trans-1-tert-butyl-3-methylcyclohexane?
A) Both groups are axial.
B) The tert-butyl group is equator ial and the methyl group is axial.
C) The tert-butyl group is axial and the methyl group is equator ial.
D) Both groups are equatorial.
E) none of the above
Answ er: B
83) Name the compound show n below .
83)
A) trans-1,3-dichlorocyclohexane
B) cis-1,3-dichlorocyclohexane
C) trans-1,2-dichlorocyclohexane
D) trans-1,4-dichlorocyclohexane
E) cis-1,2-dichlorocyclohexane
Answ er: B
84) W hich of the follow ing has tw o equatorial alkyl substituents in its most stable conformation?
A) trans-1,3-diethylcyclohexane
B) cis-1,3-diethylcyclohexane
C) cis-1,2-dimethylcyclohexane
D) cis-1,4-diethylcyclohexane
E) 1,1-dimethylcyclohexane
Answ er: B
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
85) Draw the most stable conformation of trans-1-tert-butyl-3-methylcyclohexane.
85)
Answ er:
86) Draw the most stable confor mer of cis-1-isopropyl-2-methylcyclohexane.
Answ er:
19
86)
84)
87) Draw the most stable conformation of cis-1-isopropyl-2-methylcyclohexane.
87)
Answ er:
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
88) How many constitutional isomers are possible for C6 H14 ?
A) 4
B) 8
C) 6
88)
D) 7
E) 5
Answ er: E
89) 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
Answ er: D
20
D) 2n + 2
E) 2n
89)