chapter 12 alkanes -...
Post on 26-Feb-2018
326 Views
Preview:
TRANSCRIPT
Chapter 12–1
Chapter 12 Alkanes Solutions to In-Chapter Problems 12.1 • An acyclic alkane has the molecular formula CnH2n + 2, where n is the number of carbons it
contains. • A cycloalkane has two fewer H’s than an acyclic alkane with the same number of carbons, and
its general formula is CnH2n.
a. An acyclic alkane with three carbons has eight hydrogen atoms; C3H8. b. A cycloalkane with four carbons has eight hydrogen atoms; C4H8. c. A cycloalkane with nine carbons has 18 hydrogen atoms; C9H18. d. An acyclic alkane with seven carbons has 16 hydrogen atoms; C7H16.
12.2 An acyclic alkane has the molecular formula CnH2n + 2, whereas a cycloalkane has the molecular
formula CnH2n.
a. C5H12, 5 × 2 + 2 = 12: acyclic c. C12H24, 12 × 2 = 24: cyclic b. C4H8, 4 × 2 = 8: cyclic d. C10H22, 10 × 2 + 2 = 22: acyclic
12.3 To determine if the compounds are isomers, first compare molecular formulas as in Example 12.1; two compounds are isomers only if they have the same molecular formula. Then check how the atoms are connected to each other. Constitutional isomers have atoms bonded to different atoms.
a. CH3CH2CH2CH3 and CH3CH2CH3
CH3
b. CH3CH2CH2OH and CH3OCH2CH3
c. andC4H10 C3H8
different molecular formulasnot isomers
C3H8O C3H8Osame molecular formula
different arrangement of atomsisomers
C6H12 C6H12same molecular formula
different arrangement of atomsisomers
12.4 Draw two isomers as in Example 12.2. Since isomers are different compounds with the same molecular formula, add a one-carbon branch to two different carbons to form two different molecules. Then add enough H’s to give each C four bonds.
C C C C
C C C C
C C C C
CAdd H's
Add H'sisomers
CH3CHCHCH3
CH3CCH2CH3
CH3
CH3
CH3
CH3
Add 2 C's to different carbons.C
C
C
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–2
12.5 Isopentane has 4 C’s in a row with a one-carbon branch.
CH3 CC CH3
CH3 CH3 CC C
CH3
CH3CH2 CCH3
CH3
H
H
HH
HH
HH
HH
CH3CH2CH(CH3)2a. b. c. d.
5 C's in a rownot isopentane
isopentane isopentane
isopentane
12.6 To classify a carbon atom, count the number of C’s bonded to it as in Example 12.3. Draw a complete structure with all bonds and atoms to clarify the structure if necessary.
CH3 CCH3
HCH2CH3a. CH3CH2CH2CH3 b. (CH3)3CH c.
1o
2o
1o 3o1o
2o3o
CH3 CCH3
CH3
CH3d.
1o
1o4o
12.7 Draw a structure to fit each description.
CH3CH2CH3 CH3CCH2CCH3
CH3
CH3
CH3
CH3
CH3CHCH2CH3CH3
a. b. c.
1°
4°C5H12
3° 4°2°
1°
12.8 Draw a skeletal structure for each compound.
a. b.CH3CH2CH2CH2CH2CH3 CH3(CH2)5CH3= = 12.9 Convert each skeletal structure to a complete structure with all atoms and bond lines.
a.
b.
c.C C C C C HH
HH
H
H
H
H
H
H
H
H
C C C C C H
C
H
HH
H
H H
H H
HH
HH
H
CC C
CC
C C C
HH
HH
HH
H HH
H H
H H
HH
H
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–3
12.10 To give the IUPAC name for each compound, follow the steps in Example 12.4: [1] Name the parent and use the suffix -ane since the molecule is an alkane. [2] Number the chain to give the first substituent the lower number. [3] Name and number the substituents. [4] Combine the parts.
CH3CH2CHCH2CH3
CH3
a.
5 C's in the longest chain pentane
CH3CH2CHCH2CH3
CH31 2 53
3-methylpentaneCH3CH2CHCH2CH3
CH3
methyl at C3
3
CH3CH2CH2
HCH2CH2CH2CH3C
CH3
CCH2CH2CH3
Hb.
5
methyl at C4
9 C's in the longest chain nonane
CH3CH2CH2
HCH2CH2CH2CH3C
CH3
CCH2CH2CH3
H1 2 4
CH3CH2CH2
HCH2CH2CH2CH3C
CH3
CCH2CH2CH3
H
propyl at C5
4-methyl-5-propylnonane
H CCH2CH3
CH3
CH2 CHCH3
CH3
c.
126 C's in the longest chain
hexane
H CCH2CH3
CH3
CH2 CHCH3
CH34
H CCH2CH3
CH3
CH2 CHCH3
CH324
methyls at C2 and C4
2,4-dimethylhexane
12.11 To give the IUPAC name for each compound follow the steps in Example 12.4.
24
2,3-dimethylbutanea. (CH3)2CHCH(CH3)2 C CCH3
CH3
H HCH3
CH34 C's in the longest chain
butane
C CCH3
CH3
H HCH3
CH31
methyls at C2 and C3
10 C's in the longest chain decane
4
b. CH3CH2CH2CHCH2C
CH2CH2CH2CH3
H
H
CH3CH2
CH3CH2CH2CHCH2C
CH2CH2CH2CH3
H
H
CH3CH21 2
6
ethyl at C4
4-ethyldecane
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–4
CH3CH2CH2CH2 CCH3
CH2
CCH3
CH2CH3
H
CH3
c.
12
8 C's in the longest chain octane
CH3CH2CH2CH2 CCH3
CH2
CCH3
CH2CH3
H
CH3
4 3
ethyl at C4 methyl at C3
methyl at C4
4-ethyl-3,4-dimethyloctane
12.12 To draw the structure corresponding to each IUPAC name, follow the steps in Example 12.5.
CH3CH2CHCH2CH2CH3
CH3
a. 3-methylhexane
C C C C C C C C C CC
Draw 6 C's and number the chain:
21 3 4 5Add 1 CH3
group 2 3Add H's
C
6
C
CH3CH2CCH2CH3
CH3
CH3
b. 3,3-dimethylpentane
C C C C C C C C C CC
Draw 5 C's and number the chain:
21 3 4 5Add 2 CH3
groups 2 3 Add H's
C
CH3CH2CHCH2CCH2CH2CH3
CH3
CH3
CH3
!c. 3,5,5-trimethyloctane
C C C C C C C C C CC
Draw 8 C's and number the chain:
21 3 4 5Add 3 CH3
groups 2 3Add H's
C
6
CC C C CC
C 57 8
CH3CH2CHCHCH2CH3
CH2
CH3
CH3
!d. 3-ethyl-4-methylhexane
C C C C C C C C C CC
Draw 6 C's and number the chain:
21 3 4 5Add 2 alkyl
groups 2 3Add H's
C
6
C
C
C
4
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–5
12.13 To draw the structure corresponding to each IUPAC name, follow the steps in Example 12.5.
a. 2,2-dimethylbutane
CH3CCH2CH3
CH3
CH3
C C C C C C C C
Draw 4 C's and number the chain:
21 3 4Add 2 CH3
groups 2Add H's
C
C
Add 2 alkylgroups
b. 6-butyl-3-methyldecane
CH3CH2CHCH2CH2CHCH2CH2CH2CH3
CH2CH2CH2CH3
CH3
C C C C C C C C C CC
Draw 10 C's and number the chain:
21 3 4 5 3Add H's
C
6
CC C C C
67 8
C C
9 10
C C C CC C
c. 4,4,5,5-tetramethylnonane
CH3CH2CH2C CCH2CH2CH2CH3
CH3
CH3
CH3
CH3
C C C C C C C C C C
Draw 9 C's and number the chain:
21 3 4 5Add 4 CH3
groupsAdd H's
C
6
CC C C
57 8
C
9
C
C
C
C4
C C
d. 3-ethyl-5-propylnonane
CH3CH2CHCH2CHCH2CH2CH2CH3
CH2CH3
CH2CH2CH3
C C C C C C C C C C
Draw 9 C's and number the chain:
21 3 4 5Add 2 alkyl
groupsAdd H's
C
6
CC C C
5
7 8
C
9
CC
C C C3
C C
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–6
12.14 Label the functional groups.
O
O O
alkene
ketone
alkeneester
12.15 Vitamin D3 has many nonpolar C–C and C–H bonds, which makes it water insoluble but fat soluble.
12.16 To give the IUPAC name for each compound, follow the steps in Example 12.6:
[1] Name the ring. [2] Name and number the substituents.
a.
Start numbering here.
1
Answer: methylcyclobutane
4 C's cyclobutane
methyl at C1CH3
b.
CH3CH3
Start numbering here.
1
Answer: 1,1-dimethylcyclohexane
6 C's cyclohexane
two methyls at C1
c.CH3CH2
CH2CH2CH3
5 C's cyclopentaneAnswer: 1-ethyl-3-propylcyclopentane
Start numbering here.
1 3propyl at C3
ethyl at C1
d.CH3
CH2CH3
Answer: 1-ethyl-4-methylcyclohexane
6 C's cyclohexane
methyl at C4
4
ethyl at C1
Start numbering here.
1
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–7
12.17 Give the structure corresponding to each IUPAC name.
a. propylcyclopentane
CH2CH2CH3
CH3
CH3
CH3 CH3
CH3
CH3
CH3
CH2CH3
!!d. 4-ethyl-1,2-dimethylcyclohexaneb. 1,2-dimethylcyclobutane
!c. 1,1,2-trimethylcyclopropane
1
2
12
12
4
12.18 The melting points and boiling points of alkanes increase as the number of carbons increases.
a. Highest boiling point, most carbons: decane b. Lowest boiling point, fewest carbons: pentane c. Highest melting point, most carbons: decane d. Lowest melting point, fewest carbons: pentane
12.19 Vaseline is a complex mixture of hydrocarbons, and is nonpolar, so it is insoluble in a polar
solvent like water. In a weakly polar solvent like dichloromethane, it is soluble. 12.20 Elastol is a high molecular weight alkane, making it nonpolar. By the solubility rule, “Like
dissolves like,” nonpolar oil has similar intermolecular forces to nonpolar polyisobutylene, so it is soluble in Elastol.
12.21 Write a balanced equation for each reaction. Combustion reactions release CO2 and H2O.
CH3CH2CH3 + 5 O2
+ 13 O2
a.
b. 2 CH3CH2CH2CH3
3 CO2 + 4 H2O
8 CO2 + 10 H2O
flame
flame
12.22 Write a balanced equation for the reaction. Incomplete combustion reactions release CO and H2O.
2 CH3CH3 + 5 O2 4 CO + 6 H2O Solutions to End-of-Chapter Problems 12.23 Use the formula CnH2n + 2 to determine the number of hydrogen atoms.
(31 × 2) + 2 = 64 H’s 12.24 C18H38 is the molecular formula of an acyclic alkane because it satisfies the 2n + 2 rule;
C18H2(18) + 2.
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–8
12.25 Use the formula CnH2n + 2 to determine the number of hydrogen atoms.
A C26 alkane has 54 H’s [(26 × 2) + 2 = 54]. A C27 alkane has 56 H’s [(27 × 2) + 2 = 56]. A C28 alkane has 58 H’s [(28 × 2) + 2 = 58]. A C29 alkane has 60 H’s [(29 × 2) + 2 = 60]. A C30 alkane has 62 H’s [(30 × 2) + 2 = 62].
12.26 a. A straight-chain alkane has the formula CnH2n + 2. 2n + 2 = 20; n = 9 C’s b. A branched-chain alkane has the formula CnH2n + 2. 2n + 2 = 20; n = 9 C’s c. A cycloalkane has the formula CnH2n. 2n = 20; n = 10 C’s 12.27 To form a cycloalkane, you need to form a C–C bond between 2 C’s in a chain. To do this, 1 H
from each C must be removed. This means a cycloalkane always has two fewer H’s than an acyclic alkane of the same number of C’s.
12.28 A branched-chain alkane contains one or more carbon branches bonded to a carbon chain and has
the general formula CnH2n + 2. A cycloalkane contains carbons joined in one or more rings and has the general formula CnH2n.
12.29 To classify a carbon atom, count the number of C’s bonded to it as in Example 12.3. Draw a
complete structure with all bonds and atoms to clarify the structure if necessary.
CH3(CH2)3CH3 (CH3)3CC(CH3)3
CH3CH2CHCHCH3CH3
CH3 CH3 CH3CH3
a.
b.
c.
d.
1o
2o
1o
1o2o
3o
1o 1o
4o
1o
1o
2o
3o4o
12.30 Draw a structure to satisfy the requirements.
a. b.
4°
2°
CH3CCH3
CH3
CH3
1°
only 2° C's
c.
4°
CH3CCH3
CH2CH3
CH3
d.
3°
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–9
12.31 Draw a structure to satisfy the requirements.
CH3CH2CH2CCH3
CH3
CH3a. b. CH3CH2CH2CH2CH2CH2CH3
4° only 1° and 2° C's
1° 1°2°
12.32 Yes, it is possible to have an alkane that contains only 1° carbons. It’s called ethane: CH3CH3. 12.33 To determine if the compounds are isomers, first compare molecular formulas as in Example
12.1; two compounds are isomers only if they have the same molecular formula. Then check how the atoms are connected to each other. Constitutional isomers have atoms bonded to different atoms.
and
andd.CH3
CH3
CH3 CH3
CH3CHCHCH3
CH2CH3
CH2CH3
CH3CH2CHCH2CH(CH3)2
CH3anda.
b.
c.
CH3CHCHCH3
CH2CH3
CH2CH3
andCH3CH2CHCHCH2CH3
CH3
CH3
CH3
CH3CH2CH3
C8H18 C8H18same molecular formulaconstitutional isomers
C5H10 C5H10
same molecular formulaconstitutional isomers
C8H18 C8H18same molecular formula
identical connectivityidentical
C8H16 C8H16
same molecular formulaconstitutional isomers
12.34 To determine if the compounds are isomers, first compare molecular formulas as in Example
12.1; two compounds are isomers only if they have the same molecular formula. Then check how the atoms are connected to each other. Constitutional isomers have atoms bonded to different atoms.
and
andd.
CH3CH2CH2CH3 CH3CH2CH2CH2CH3 anda.
b.
c.
CH3(CH2)4CH3andCH3CH2
C4H10 C5H12
different molecular formulasnot isomers
C5H12 C5H10
different molecular formulasnot isomers
C6H14 C6H14same molecular formula
identical connectivityidentical
C3H6O2 C3H6O2
same molecular formulaconstitutional isomers
H2C CH2
CH2CH3
CH3CH2CH2CH2CH3
CO
OCH3CH3 C
O
OHCH3CH2
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–10
12.35 To determine if the molecules are constitutional isomers or identical, determine if the atoms are connected to each other in the same way.
H CCH3
CH2CH2CH3
CH3
5 C's in a rowCH3 bonded to second C
CH3CHCHCH3
CH3
CH3
CH3CHCH3
CH2CH2CH3
CH3
CH3CHCH2CH2
CH3 CH2CH3
CH3CHCH2CH3a. b. c. d. e.
4 C's in a rowconstitutional isomers
5 C's in a rowidentical
5 C's in a rowCH3 bonded to middle Cconstitutional isomers
5 C's in a rowidentical
5 C's in a rowidentical
12.36 To determine if the molecules are constitutional isomers or identical, determine if the atoms are
connected to each other in the same way.
and
andd.
CH3(CH2)3CHCH3 anda.
b.
c.
and
C7H16 C7H16
same molecular formulaconstitutional isomers
C7H16
same molecular formulaconstitutional isomers
C7H16
same molecular formulaidentical connectivity
identical
same molecular formulaidentical connectivity
identical
CH3
C7H16
CHCH3
HCH2CH2CH2 C
H
CH3
H
CH3(CH2)3CHCH3
C7H16CH3
CH3CH2CH2CHCH2CH3
CH3
C7H16
CH3CH2CH2CHCH2CH3
CH3
C7H16
CH3CH2CHCH2CH2CH3CH3
e. CH3(CH2)3CHCH3
C7H16CH3
and
C7H16
CH3CH2CHCH2CH2CH3CH3
same molecular formulaconstitutional isomers
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–11
12.37 Draw structures that fit each description.
CH3
a.
b. CH3CH2CH2CH2CH2OH CH3OCH2CH2CH2CH3
CH2CH3
c. CH3CH2CH2Cl CH3CHCH3
Clcycloalkanes
constitutional isomersC7H14
constitutional isomersC5H12O
etheralcohol
constitutional isomersC3H7Cl
12.38 Draw all of the structures that satisfy the criteria.
CH3CH2CH2CH2CH2CH3 CH3CHCH2CH2CH3 CH3CH2CHCH2CH3
CH3 CH3
CH3CCH2CH3CH3
CH3CH3CHCHCH3
CH3
CH3 12.39 Draw all of the structures that satisfy the criteria.
CH3CHCH2CH2CH2CH2CH3 CH3CH2CHCH2CH2CH2CH3 CH3CH2CH2CHCH2CH2CH3
CH3 CH3 CH3
molecular formula C8H187 C's in the longest chain
one CH3 group bonded to each chain 12.40 Draw all of the structures that satisfy the criteria.
CH3 CH3
CH3
CH2CH3 CH3H3C
12.41 Draw all of the structures that satisfy the criteria.
molecular formula C3H6O: CH3CCH3
O OOH CH3
alcohol ketone cyclic ether
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–12
12.42 Draw one constitutional isomer for each molecule.
a.CO
CH3CH3CH2CO
H CH2CH2CH3
b. CH3CH2CHCH3
NH2CH3CH2CH2CH2NH2
c.
OH
CH2OHone isomer of is
one isomer of is
one isomer of is
12.43 Give the IUPAC name for each molecule.
CH3CH2CH2 C CH3
CH3
HCH3CH2 C CH2CH2
CH3
HCH3CH2 C CH3
CH3
CH3
C C CH3
CH3
HCH3CH2CH2CH2CH2CH3
hexane 2-methylpentane 3-methylpentane 2,2-dimethylbutane 2,3-dimethylbutane
CH3
CH3
H
12.44 Give the IUPAC name for each molecule.
CH3 CH3
CH3
CH2CH3 CH3H3C
cyclopentane methylcyclobutane 1,2-dimethylcyclopropane ethylcyclopropane 1,1-dimethylcyclopropane 12.45 Give the IUPAC name for each molecule.
CH3CH2CH2 C CH2CH2CH3
CH3
H
7 C's = heptane4-methylheptane
41
C
CC
C
C
CH2CH3
H
HHH
H
HH
H H
5 C's in a ring = cyclopentaneethylcyclopentane
a. b.
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–13
12.46 Give the IUPAC name for each molecule.
3
1
a. CH3CH2CH2CH2 CCH3
HCH2CH3
7 C's = heptane3-methylheptane
b.C CC C
HH H
H
H
CH3CH3
H
4 C's in a ring = cyclobutane1,2-dimethylcyclobutane
1 2
12.47 To give the IUPAC name for each compound, follow the steps in Example 12.4.
CH3CH2CHCH2CH2CH2CH3
CH3
CH3CH2CHCH2CHCH2CH2CH3
CH3 CH3
CH3CH2CH2C(CH2CH3)3
CH3CHCH2C HCH2CH3
CH2CH3
CH2CHCH3
CH3
a.
b.
c.
d.
(CH3CH2)2CHCH2CH2CH2CH(CH3)2
CH3CH2 CCH3
CH3
CH2CH2
CH2CH2CH2 CCH3
CH3
CH3
e.
f.
2,2,8,8-tetramethyldecane
7 C's = heptane
31
methyl at C3
3-methylheptane
31 5
methyls at C3 and C5
8 C's = octane3,5-dimethyloctane
CH3CH2CH2CCH2CH3
CH2CH3
CH2CH3
6 C's = hexane3,3-diethylhexane
3 1
two ethyls at C3
12
4
6methyls at C2 and C6
ethyl at C4
4-ethyl-2,6-dimethyloctane8 C's = octane
CCH2CH2CH2CCH3CH3CH2
CH3CH2
H CH3
H
8 C's = octane6-ethyl-2-methyloctane
1
methyl at C2
ethyl at C6 2
10 C's = decane
two methyls at C2two methyls at C8
12
8
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–14
12.48 To give the IUPAC name for each compound, follow the steps in Example 12.4.
a.
b.
c.
d.
e.
5 C's = pentane
2
1
2,3-dimethylpentane
6 C's = hexane3,3-dimethylhexane
CH
CH2CH3
CHCH3CH3
CH3
CH3CH2 CCH3
CH3
CH2CH2CH3
13 2 methyls at C3
9 C's = nonane5-ethylnonane
CH3CH2 CHCH2CH2CH2CH3
CH2CH2CH2CH3
15
ethyl at C5
(CH3CH2)2CHCH(CH2CH3)2
CH
CHCH2CH3CH3CH2CH2CH3
CH3CH21
3
4
6 C's = hexane3,4-diethylhexane
2 ethyls at C3 and C4
6 C's = hexane
1
4-ethyl-2,2-dimethylhexane
CCH3
CH3
CH2CH3 CH
CH2CH3
CH2CH3
ethyl at C4
2 methyls at C224
f.
8 C's = octane
1
5-ethyl-2,6-dimethyloctane
CH
CH3
CH2CH2CH3 Cethyl at C5CH2CH3
HCHCH2CH3
CH32 5 62 methyls at C2 and C6
3
5methyl at C3
methyl at C2
12.49 To give the IUPAC name for each compound, follow the steps in Example 12.6.
a.
b.
c.
d.CH3
CH3CH3
CH3CH3
CH3CH2 CH2CH3
6 C's = cyclohexane1,3-diethylcyclohexane
8 C's = cyclooctane
3 C's = cyclopropanemethylcyclopropane
methyl
4 C's = cyclobutane1,1,2,2-tetramethylcyclobutane
1
2
1 3
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–15
12.50 To give the IUPAC name for each compound, follow the steps in Example 12.6.
a.
b.
c.
d.
6 C's = cyclohexane4-butyl-2-ethyl-1-methylcyclohexane
7 C's = cycloheptane
6 C's = cyclohexane1-butyl-2-propylcyclohexane
propyl
CH2CH3 ethyl
ethylcycloheptane
CH2CH2CH3
CH2CH2CH2CH3
1
2
butyl
CH2CH2CH3
CH2CH3
1propyl
ethyl
5 C's = cyclopentane1-ethyl-1-propylcyclopentane
CH2CH2CH2CH3
CH3CH2
CH3
1 4
2 butylethyl
methyl
12.51 Give the structure corresponding to each IUPAC name.
a. 3-ethylhexane
CH3CH2CHCH2CH2CH3
CH2CH3
b. 3-ethyl-3-methyloctane
CH3CH2CCH2CH2CH2CH2CH3
CH3
CH2CH3
ethyl at C3
methyl at C3
ethyl at C3
CH3CHCHCHCHCH2CH2CH2CH2CH3
c. 2,3,4,5-tetramethyldecane
CH3 CH3
CH3 CH3
d. cyclononane
e. 1,1,3-trimethylcyclohexaneCH3 CH3
CH3
f. 1-ethyl-2,3-dimethylcyclopentane
CH2CH3
CH3
CH3
four methyl groups at C2, C3, C4, and C5
three methyl groups
ethyl at C1
two methyl groups
1 2
3
12
3
12.52 Give the structure corresponding to each IUPAC name.
a. 3-ethyl-3-methylhexane
CH3CH2CCH2CH2CH3
CH2CH3
d. 1,3,5-triethylcycloheptane
ethyl at C3
CH3 methyl at C3 CH2CH3
CH2CH3
H3CH2C three ethyls at C1, C3, C5
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–16
e. 3-ethyl-3,4-dimethylnonane
CH3CH2C
b. 2,2,3,4-tetramethylhexane
CH3C4 methyls at C2, C3 and C4
CH3
CH3
CH CHCH2CH3
CH3 CH3 CH2CH3
CH3
CHCH2CH2CH2CH2CH3
CH3
ethyl at C3
2 methyls at C3, C4
f. 2-ethyl-1-methyl-3-propylcyclopentanec. 4-ethyl-2,2-dimethyloctane
CH3CCH3
CH3
CH2CHCH2CH2CH2CH3
CH2CH3 ethyl at C4
2 methyls at C2 CH3
CH2CH3
CH2CH2CH3
methyl at C1
ethyl at C2
ethyl at C4 12.53 Explain why each IUPAC name is incorrect. a. 2-methylbutane: Number to give CH3 the
lower number, 2 not 3.
CH3CHCH2CH3CH3
C2
d. 2,5-dimethylheptane: longest chain not chosen
CH3CHCH2CH2CHCH2CH3CH3 CH3
b. methylcyclopentane: no number assigned if only one substituent
CH3
e. 1,3-dimethylcyclohexane: Number to give the second substituent the lower number.
CH3
CH3
C1
C3
c. 2-methylpentane: five-carbon chain
CH3CHCH2CH2CH3CH3
f. 1-ethyl-2-propylcyclopentane: lower number assigned alphabetically
CH2CH3C1
CH2CH2CH3C2
12.54 Explain why each IUPAC name is incorrect. a. 2-methylpentane: Number to give CH3 the
lower number (i.e., 2 not 4).
CH3CHCH2CH2CH3CH3
C2
d. 3,5-dimethylheptane: longest chain not chosen
CH3CH2CHCH2CHCH2CH3
CH3 CH3
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–17
b. 2,2,3-trimethylbutane: Number to give lower numbers to CH3 groups.
CH3CCH3
CH3
CHCH3
CH3
e. 1-ethyl-1-methylcycloheptane: number ring starting with substituents
CH3
CH2CH3
c. 3-methylhexane: six-carbon chain
CH3CH2CHCH2CH2CH3CH3
f. 1,2-diethylcyclohexane: number to give substituents lowest numbers
CH2CH3
CH2CH3
C2 not C6
12.55 Draw the isomers and then give the IUPAC name.
CH3
CH3
CH3
CH3
CH3CH3
1,2-dimethylcyclopentane 1,3-dimethylcyclopentane 1,1-dimethylcyclopentane 12.56 Draw the isomers and then give the IUPAC name.
ethylcyclobutane 1,2-dimethylcyclobutane
CH3CH3
1,1-dimethylcyclobutane
CH2CH3CH3
CH31,3-dimethylcyclobutane
CH3
H3C
12.57 Draw a skeletal structure for each compound.
CH3CHCH2CH2CH2CH2CH3
CH3
a. octane b. 1,2-dimethylcyclopentane c.CH3
CH3 12.58 Draw a skeletal structure for each compound.
a. CH3(CH2)7CH3 b. 1,1-diethylcyclohexane c. (CH3CH2)2CHCH2CH2CH3
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–18
12.59 Convert each structure to a complete structure with all atoms drawn in.
C C C C C C C C C HCH
HH
H
H H
H H
H H
H H
H H
H
H
H
H
H H
HC C C C HC
H
HH
C
H H
H
H H
H
CHHHH
H
C CCC
C CH H
H
H
H
H
HHH
HH
H
H
a. b. c.
12.60 Convert each structure into a complete structure with all atoms drawn in.
a. b. c.
CH
HH
CH
HCH
HC
C
HCH
HCH
CH
HC
H
H
HCH
HH
HH
H
C C
CC
C
H H
HH
HH
HH
HCH
HCH
HCH
HCH
HH
CH
HH
CH
HCH
C
CH
CH
C
CH
HH
H
H HH
H HH
12.61 The melting points and boiling points of alkanes increase as the number of carbons increases.
a. or
more carbon atomshigher melting point
b. or
more carbon atomshigher melting point
12.62 The melting points and boiling points of alkanes increase as the number of carbons increases.
cyclobutane or cyclopentanea. b.more carbon atoms
higher boiling pointmore carbon atoms
higher boiling point
cyclopentane or ethylcyclopentane
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–19
12.63 Branched alkanes have lower boiling points than linear alkanes.
a. increasing boiling point: (CH3)4C < (CH3)2CHCH2CH3 < CH3CH2CH2CH2CH3
b. increasing boiling point: (CH3)2CHCH(CH3)2 < CH3CH2CH2CH(CH3)2 < CH3(CH2)4CH3
most branching no branching
most branching no branching 12.64 The boiling points of heptane and H2O are similar, even though heptane has a much higher
molecular weight and greater surface area, because H2O can form intermolecular hydrogen bonds, thus giving water a much higher boiling point than would otherwise be expected of such a low molecular weight compound. Heptane is a nonpolar molecule and cannot form hydrogen bonds.
12.65 Hexane is a nonpolar hydrocarbon, making it soluble in organic solvents like dichloromethane,
but insoluble in water. 12.66 Vaseline, a solid, contains a larger number of carbon atoms than mineral oil, a liquid. The melting
point increases with increasing number of carbon atoms. 12.67 Write a balanced equation for each reaction. Combustion reactions form CO2 and H2O.
a. b.2 CH3CH3 + 7 O2 4 CO2 + 6 H2O (CH3)2CHCH2CH3 + 8 O2 5 CO2 + 6 H2O
12.68 Write a balanced equation for each reaction. Combustion reactions form CO2 and H2O.
a. b. + 9 O2 6 CO2 + 6 H2O + 15 O2 10 CO2 + 10 H2O2
12.69 Write a balanced equation for each reaction. Incomplete combustion reactions form CO and H2O.
a. b.2 CH3CH2CH3 + 7 O2 6 CO + 8 H2O 2 CH3CH2CH2CH3 + 9 O2 8 CO + 10 H2O 12.70 Write a balanced equation for the reaction. Incomplete combustion reactions form CO and H2O.
2 C6H6 + 9 O2 12 CO + 6 H2O 12.71 Write a balanced equation for the oxidation of glucose to form CO2 and H2O.
C6H12O6 + 6 O2 6 CO2 + 6 H2O 12.72 Write a balanced equation for the combustion of ethanol to form CO2 and H2O.
CH3CH2OH + 3 O2 2 CO2 + 3 H2O 12.73 Higher molecular weight alkanes in warmer weather means less evaporation. Lower molecular
weight alkanes in colder weather means the gasoline won’t freeze.
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–20
12.74 The concrete foundation of a new house is often wrapped in polyethylene, a high molecular weight alkane, to prevent water from seeping into the house. The nonpolar alkane will not allow the polar water molecules to pass through.
12.75 The mineral oil can prevent the body’s absorption of important fat-soluble vitamins. The vitamins
dissolve in the mineral oil, and are thus not absorbed. Instead, they are expelled with the mineral oil.
12.76 A fire in a fireplace in a poorly ventilated room poses a health hazard, because incomplete
combustion forms carbon monoxide, a toxic gas. The concentration of CO can reach an unhealthy level if the room does not allow proper ventilation.
12.77 c. The nonpolar asphalt will be most soluble in the paint thinner because “like dissolves like.”
The liquid alkanes of the paint thinner dissolve the high molecular weight hydrocarbons of the asphalt.
12.78
CO
O (CH2)16CH3H2C
C CO
O (CH2)16CH3H
CO
O (CH2)16CH3H2C
a.
3 ester groups
CO
O (CH2)16CH3H2C
C CO
O (CH2)16CH3H
CO
O (CH2)16CH3H2C
!+ !" !"!+
!+!"
!+ !"
!"
!"!+
!+
b.
c. Tristearin will dissolve in an organic solvent like hexane because it is also an organic molecule and “like dissolves like.” Tristearin does not dissolve in water because the nonpolar chains on the molecule are too large, making the compound insoluble in water even though the ester portion of the molecule is polar.
12.79 Answer each question about the compound.
CH3CH2CH2 CCH3
CH3
CCH2CH3
HCH2CH3a.
CH3CH2CH CCH3
HCCH2CH3
HCH2CH3
CH3
c. not water solubled. soluble in organic solvents
C11H24 + 17 O2 11 CO2 + 12 H2Oe.
f.
7 C's = heptane3-ethyl-4,4-dimethylheptane
b.
constitutional isomer
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Chapter 12–21
12.80 Answer each question about the compound.
CH3CH2CH2 CH
CCH2CH3
CH3
CH2CH3a.
CH3CH2CH2 CCH3
HCCH2CH3
CH2CH3
CH2CH3
c. not water solubled. soluble in organic solvents
2 C12H26 + 37 O2 24 CO2 + 26 H2Oe.
f.
7 C's = heptane3,4-diethyl-3-methylheptane
b.
constitutional isomer
CH3CH2
12.81
c. not water solubled. soluble in organic solvents
C8H16 + 12 O2 8 CO2 + 8 H2Oe.
f.constitutional isomer
a.
5 C's in a ring = cyclopentanepropylcyclopentane
b. CH3
CH3CH2
12.82
c. not water solubled. soluble in organic solvents
C8H16 + 12 O2 8 CO2 + 8 H2Oe.
f.constitutional isomer
a.
4 C's in a ring = cyclobutane1,1-diethylcyclobutane
b.CH2CH3
CH2CH3
CH2CH3
CH2CH3
12.83 A compound with 10 carbons and two rings will have 2n – 2 H’s.
(10 × 2) – 2 = 18 C10H18
12.84 Draw the 12 constitutional isomers of C6H12 that contain one ring.
12.85 Cyclopentane has a more rigid structure. The rings can get closer together since they are not
floppy, resulting in an increased force of attraction. Therefore, the boiling point is higher.
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
Alkanes 12–22
12.86 Draw the structures of the seven constitutional isomers of C4H10O.
OH
OHO
OOH
OH O
�������E\�0F*UDZ�+LOO�(GXFDWLRQ��7KLV�LV�SURSULHWDU\�PDWHULDO�VROHO\�IRU�DXWKRUL]HG�LQVWUXFWRU�XVH��1RW�DXWKRUL]HG�IRU�VDOH�RU�GLVWULEXWLRQ�LQ�DQ\�PDQQHU��7KLV�GRFXPHQW�PD\�QRW�EH�FRSLHG��VFDQQHG��GXSOLFDWHG��IRUZDUGHG��GLVWULEXWHG��RU�SRVWHG�RQ�D�ZHEVLWH��LQ�ZKROH�RU�SDUW�
top related