Organic Chemistry
Name____________________ Hr___
The alkanes are a homologous series (compounds with the same general formula). One member
of the series differs from the next by a –CH2- group. Naming the series follows a pattern.
Carbon chains with only single bonds are alkanes; their names all end in –ane. If they are
straight chains with no branches, they follow this pattern:
Alkane name
Formula
Number of carbons
methane
1
ethane
2
propane
3
butane
4
pentane
5
hexane
6
heptane
7
octane
8
nonane
9
decane
10
The italic part of each name is the prefix. The prefixes will be used
Branch prefix
methyl
ethyl
propyl
butyl
with different endings in other groups of organic compounds. When the
alkanes are branched, the rules for naming are as follows:
1.
Find the longest continuous chain of carbons in the molecule. The name of this part of the molecule will be
the base name, chosen from the list above.
2. Number the carbons in the main chain in sequence. Start on the end of the molecule that is closest to an
attached group, so that the group is attached to the carbon with the smallest number.
3. Name the attached groups by using the branch prefix above.
4. Add numbers to the names of the attached alkyl group to identify their position on the chain. The number
comes first and is connected to the name with a hyphen.
5. Use prefixes to indicate more than one attached alkyl group in the structure. These prefixes are di-, tri-,
and tetra-.
Example: Name the following branched alkane:
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CH3
CH3
CH3-CH-CH2-CH2-CH-CH2-CH3
The longest continuous chain has seven carbons. Therefore, this is a heptane.
Numbering starts on the left and continues to the right.
The attached groups have single carbons, so they are methyl groups.
One methyl is attached to carbon number 2 of the heptane chain.
The other methyl is attached to carbon number 5.
There are two attached methyl groups, so this is dimethyl.
Name the following organic compounds.
Use the rules on the reverse side to name the following organic compounds
CH3 CH2-CH3
a. CH3-CH2- C- CH2-CH-CH2-CH3
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CH3
b. CH3- CH CH-CH3
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CH3-CH2 CH3
c. CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
________________________________
CH3
1. CH3-CH2-CH2-CH2-CH2-CH3
2. CH3-CH-CH2-CH3
CH3
3. CH3-CH2-CH-CH2-CH3
CH2-CH3
4. CH3-C-CH2-CH2-CH3
CH3
CH3
5. CH3-CH-CH-CH3
CH3
CH3
6. CH2-CH2-CH2-CH2
CH3
CH3
CH3 CH3
7. CH3-CH- C-CH3
CH3
CH2
8. CH3-CH-CH2-CH-CH2-CH3
CH2
CH3
9. Which of the above (#1-8) are isomers?____________________
Draw the following structures:
1.
nonane
2.
2-methylpropane
3.
2-methylbutane
4.
4-methyldecane
5.
3-ethylhexane
6.
2,2-dimethylpentane
7.
2,4 dimethylpentane
8.
2,2,4 trimethylhexane
9. 3-ethyl-4-methylhexane
10.
2-ethyl-3,3-dimethyloctane
This structure is named wrong, write
the correct name.
Draw and name three isomers for each of the following molecular formulas.
1. C8H18
Isomer #1
Isomer #2
Name________________
Name_________________
1.
C9H20
Isomer #1
Isomer #2
Name________________
Name_________________
1.
C10H22
Isomer #1
Isomer #2
Name________________
Name_________________
Isomer#3
Name__________________
Isomer#3
Name__________________
Isomer#3
Name__________________