Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
Organic Nomenclature Package A
Organic compounds​: compounds that contain carbon, except CO​(g)​, CO​2(g)​, and ionic compounds with carbon.
Hydrocarbons​: organic compounds that contain only carbon and hydrogen atoms in their molecular structure.
A. Straight Chain Alkanes
Alkanes:​ a hydrocarbon with only single bonds between carbon atoms
IUPAC Name
Molecular
formula
Methane
CH​4
Ethane
C​2​H​6
Propane
C​3​H​8
Butane
C​4​H​10
Pentane
C​5​H​12
Hexane
C​6​H​14
Heptane
C​7​H​16
Octane
C​8​H​18
Nonane
C​9​H​20
Decane
C​10​H​22
-ane
C​n​H​(2n+2)
1​ | ​Page
Structural formula
Line formula
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
B. Haloalkanes
These are alkanes with halogens attached -iodine, bromine, chlorine and fluorine.
Examples:
2-chlorohexane
1-chlorobutane
CH​2​ClCH​2​CHICH​2​CH​2​CH​2​CH​2​CH​3
1,2-dibromopentane
1-chloro-3-iodooctane
Part B Practice:
i.
Draw the structures for each of the following:
a. Triiodomethane
b. 1-chloropropane
c. Bromoethane
d. 2,2-dichloroheptane
e. 4-bromo-1,2-dichloro-6-iodohexane
f. 1,3,5-tribromooctane
2​ | ​Page
Grade 12 University Prep. Chemistry
SCH4U
ii.
a.
Unit 2 – Organic Chemistry
Give the name for each of the following structures:
b.
c.
d.
e.
f.
CCl​3​CH​2​CH​2​CHBrCH​2​CHBrCH​2​CH​2​CH​3
Additional Practice:​
p. 49#85-88, 90-93, 95acd
C. Branch-Chain Alkanes
Alkyl group​: a hydrocarbon group derived from an alkane by the removal of a hydrogen atom.
Alkyl groups that can be added to hydrocarbon chains:
3​ | ​Page
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
Nomenclature steps:
1)
Find the longest carbon chain. This will be the parent chain.
2)
Start numbering the carbons on the parent chain starting at the carbon closest to the first branch.
3)
Write branches in ​alpha order​, not numerically.
Ex. 1
The
longest carbon chain is 5 carbons long. The parent chain is pentane
There
are two branches. A methyl group and a ethyl group.
Therefore, this hydrocarbon is ​3-ethyl-2-methylpentane
If there are more than one of the same type of alkyl group, use the ​di, tri, ​etc. prefixes.
Ex. 2
2,3-dimethylpentane
Structural Isomers:​ chemicals with the same molecular formulas but have different structural formulas and
different names.
Ex. 3​ - C​4​H​10
butane
isobutane ​or​ 2-methylpropane
More examples:
2-methylpropane
4​ | ​Page
2,4-dimethylpentane
Grade 12 University Prep. Chemistry
SCH4U
2,2,4-trimethylpentane
Unit 2 – Organic Chemistry
2-chloro-3-ethyl-4,4-dimethylheptane
CH​3 C(CH​
​
3​)​2 CH​
​
2​CH​3
2,2-dimethylbutane
3-isopropyl-2,4-dimethylpentane
Part C Practice
i.
Draw the structures of the following compounds:
a. 2-methylbutane
b. 4-ethyl-2-methylheptane
c. 3,3-dimethyloctane
ii.
d. 3,3-dibromo-4-isopropyl-2-methylnonane
Name the following structures:
a.
b.
c.
5​ | ​Page
d.
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
f.
e.
g.
h.
CH​3​CHBrCH(CH​2​CH​3​)CH​2​CH(CH​3​)CH​2​CH​3
From textbook:​
Read pg 15-21 Do pg 19 # 1-11; pg 21 #12-14, 16-21
D. Alkenes
Alkene:​ a hydrocarbon with one or more double bonds between carbon atoms
Nomenclature steps:
1)
Find the longest carbon chain. This will be the parent chain.
2)
If the carbon chain contains a double bond, use the suffix ​–ene
If the carbon chain contains a triple bond, use the suffix ​-yne
3)
Start numbering the carbons on the parent chain starting at the carbon closest to the largest
multiple bond.
4)
Write branches in ​alpha order​, not numerically.
Ex. 1
6​ | ​Page
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
The longest carbon chain is 5 carbons long. The parent chain is
pentane
There is a double bond starting at the 2​nd​ carbon
Therefore, this hydrocarbon is ​pent-2-ene
If there is only one multiple bond and it is on the first carbon, there is no need to prefix the name with the
number 1.
ie. pent-1-ene can simply be called pentene.
If there is more than one multiple bond, use the ​di, tri, ​etc. prefixes as before.
Ex. 2
The longest carbon chain is 7 carbons long. The parent
chain is heptane
There are double bonds on the 2​nd​ and 4​th​ carbons
Therefore, this hydrocarbon is ​2,4-heptadiene or hept​a​-2,4-​di​ene
More Examples:
4-methylpent-2-ene
hex-3-ene
CH​2 -C(CH​
​
3​)-CCl-CH-CH​2 -CH​
​
3
2-methylhex-3-ene
3-chloro-2-methylhexa-1,3-diene
CH​2​Br-C(CH​3​)-CH-CH​3
2,5-dimethylhexa-1,3,5-triene
1-bromo-2-methylbut-2-ene
Part D Practice:
i.
Draw the structures of the following compounds:
a. propene
b. 2-bromo-3-ethylpent-1-ene
7​ | ​Page
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
c. buta-1,3-diene
d. 2,3-dimethylhexa-2,4-diene
e. 2,2-dimethylhept-3-ene
f.
ii.
Name the following compounds:
a.
b.
c.
d.
e.
f.
8​ | ​Page
3-isopropylhex-3-ene
Grade 12 University Prep. Chemistry
SCH4U
Additional practice from textbook:​
Unit 2 – Organic Chemistry
p. 26#23-34, p. 27#35-44
Cis / Trans Isomers
Looking at 2-pentene, the hydrogens located on the 2​nd​ and 3​rd​ carbons are on the same side, however it is
possible for them to be on opposite sides, as well. These are two different isomers of 2-pentene. Therefore, we
must distinguish between them. When hyrdogens are on the ​same​ side of the double (or triple) bond, we use the
suffix ​cis​, if they are on ​opposite​ sides we use ​trans​.
cis-pent-2-ene
Draw the ​cis ​and ​trans​ isomers of the following:
9​ | ​Page
trans-pent-2-ene
Grade 12 University Prep. Chemistry
SCH4U
10​ | ​Page
Unit 2 – Organic Chemistry
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
E. Alkynes
Alkynes:​ a hydrocarbon with one or more triple bonds between carbon atoms
Ex. 1
The longest carbon chain is 6 carbons long. The parent chain is
hexane
There is a triple bond starting at the 2​nd​ carbon
Therefore, this hydrocarbon is ​2-hexyne or hex-2-yne
Ex. 2
The longest carbon chain is 6 carbons long. The parent chain is
hexane
There is a double bond on the 1​st​ carbon and a triple bond starting at the
2​nd​ carbon
Therefore, this hydrocarbon is ​1-hexen-4-yne or hex-1-en-4-yne
More Examples:
ethyne
11​ | ​Page
1,3-pentadiyne
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
2,6-dimethylhept-3-yne
6-methyloct-5-en-1-yne
Part E Practice
i.
Draw the structure of the following compounds:
a. pent-2-yne
b. 4-ethylhex-2-yne
c. 3,3-dimethylbut-1-yne
ii.
d. 1,2-difluorohex-2-en-4-yne
Name the following compounds:
a.
b.
c.
d.
12​ | ​Page
Grade 12 University Prep. Chemistry
SCH4U
e.
Unit 2 – Organic Chemistry
f.
Additional practice from textbook:​
p. 30 #45-52
F. Cycloalkanes/enes
Acyclic hydrocarbons​: open-chain hydrocarbons without any rings of carbon atoms.
Alicyclic hydrocarbons: ​hydrocarbons with a carbon-carbon bond structure forming a closed ring. Sometimes
just called​ cyclic​ hydrocarbons
Nomenclature
A cyclic compound has the prefix ​cyclo-​ to indicate the ring structure.
C​6​H​14
13​ | ​Page
C​6​H​12
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
When cyclic hydrocarbons have multiple substituent groups, or branches, they are listed in ​alphabetical order​,
and the first substituent is assigned to the ​lowest​ carbon #.
Ex. 1
Nomenclature for cyclic alkenes and alkynes is the same as cylcoalkanes, except that numbering ​starts​ at the
multiple bond.
Ex. 2
Aromatic Compounds
Originally meant odourous, but the definition has been altered to mean a compound that contains a ​benzene​ ring.
1,3,5-cyclohexantriene OR cyclohexa-1,3,5-triene (aka benzene​):
14​ | ​Page
Grade 12 University Prep. Chemistry
SCH4U
Unit 2 – Organic Chemistry
More Examples:
Cyclohexene
Cyclopentane
cyclohexa-1,3,5-triene (aka
benzene)
3-methylcyclooctene
Practice:
i.
Draw the structures of the following compounds:
a. cyclopentene
b. 1-ethyl-3-methylcyclopentane
c. methylcyclohexane
d. cyclohexa-1,3-diene
e. 1,3,5-trimethylcycloheptane
f.
15​ | ​Page
1,2,3,4,5,6-hexachlorocyclohexane
Grade 12 University Prep. Chemistry
SCH4U
ii.
Unit 2 – Organic Chemistry
Name the following compounds:
a.
b.
c.
d.
e.
f.
Additional practice from textbook:​
16​ | ​Page
p.34 # 55-64; pg 38 #65-74