SCH4U: Organic Nomenclature: Alkanes: Answers
1)
a) methylpropane
b) 2,3-dimethylpentane
c) 3-ethyl-4-methylhexane
d) 5-ethyl-2,2,4-trimethyloctane
e) 4-ethyl-2,2,7-trimethyl-5-propyldecane
2)
3)
a) cyclopentane
b) cyclohexane
c) 1-ethylcyclobutane
d) 1,2-dimethylcyclopentane
4)
5)
Here are 6 possible structural isomers with the formula C 7H 16 (there are others...)
SCH4U: Organic Nomenclature: Alkenes: Answers
1)
a) 2-pentene
b) 2-methyl-2-butene
c) 3,4,5-trimethyl-2-hexene
d) cyclohexene
e) methylpropene
f) 4-ethyl-1-methylcyclopentene
g) 4-methyl-3-propyl-1,3-pentadiene
2)
3)
c) cis-3-hexene
d) trans-3-octene
4)
The double bond does not allow for the free rotation of the carbon atoms about the bond axis, thus locking
the atoms on either side of the double bond into a fixed position.
5)
The following are 7 possible structural isomers of C 5H 10 (there may be others...)
SCH4U: Organic Nomenclature: Alkynes: Answers
1)
a) 2-butyne
d) 4-methyl-2-pentyne
b) 4-methyl-2-pentyne
c) 3,3,5-trimethyl-1-heptyne
e) 6-ethyl-3,7-dimethyl-4-nonyne
f) 3-methyl-1-pentyne
2)
3)
a) sp3 hybridization (tetrahedral) with bond angles of 109.5E
C 1(2sp3 )-sigma-C 2(2sp3 )
[C 1(2sp3 )-sigma-H(1s)]X3
[C 2(2sp 3)-sigma-H(1s)]X3
b) sp2 hybridization (planar triangular) with bond angles of 120E
C 1(2sp2 )-sigma-C 2(2sp 2)
[C 1(2sp 2)-sigma-H(1s)]X2
C 1(2p)-pi-C 2(2p)
[C 2(2sp 2)-sigma-H(1s)]X2
c) sp hybridization (linear) with bond angles of 180E
C 1(2sp)-sigma-C 2(2sp)
C 1(2sp)-sigma-H(1s)
4)
[C 1(2p)-pi-C 2(2p)]X2
C 2(2sp)-sigma-H(1s)
The alkanes have only strong sigma bonds between all of the atoms in their molecules. W ith these
bonding electrons localized directly between the atoms within the plane of the molecule, they are hard to
access by incoming reactive molecules. As a result these hydrocarbons are relatively inert.
The alkenes and alkynes on the other hand have at least one pi bond in between the carbon atoms in their
molecules. These bonding electrons form exposed clouds above and below the plane of the molecule, and
are easily attacked by incoming reactive molecules. As a result, these pi bonds are easily broken, making
these hydrocarbons considerably more reactive.
SCH4U: Organic Nomenclature: Aromatics: Answers
Reactions involving Benzene:
Naming Aromatic Compounds
4-methyl-3-phenyl-1-pentene
1-ethyl-3-isopropyl-2-methylbenzene
para-diisopropylbenzene
1,2,4-triethylbenzene
3,5-dimethyl-4-phenyloctane
phenylethene
SCH4U: Organic Nomenclature: Hydrocarbon Nomenclature Review: Answers
a) 3-ethyl-4-methyl-2-pentene
b) 5-isopropyl-1,3-cyclopentadiene
c) 3-ethyl-6-methyl-4-octyne
d)
e)
f)
g) 1,4-diethylbenzene (or para)
h) 3-ethyl-6-methyl-5-propylnonane
i) 1,4-diethyl-2,3-dimethyl
cycloheptane
j)
k)
l)
m) 4-isopropyl-3,6-dimethyl-2,5octadiene
n) 4-ethyl-5-methylcyclohexene
o) 2,5-dimethyl-3-phenylhexane
p)