Download 1.1-3 Nomenclature

Nomenclature
L.O.:
 Name simple hydrocarbons.
 Draw the structural formula from a given
hydrocarbon name.
Starter questions
1.
2.
a.
b.
c.
d.
e.
f.
g.
3.
What is a hydrocarbon?
Draw and name these molecules:
CH4
C2H6
C2H4
C2H2
C2H5OH
C2H5Br
C2H3 OOH
What families, or groups of hydrocarbons do
each of these belong to?
Hydrocarbons are organic compounds hat
contain carbon and hydrogen only.
Saturated hydrocarbon: single bonds only
Unsaturated hydrocarbon: multiple carbon-tocarbon bonds
Aliphatic hydrocarbon: carbon atoms joined
together in straight or branched chains.
Alicyclic hydrocarbon: carbon atoms joined in a
ring structure.
This compounds belong to the same family.
How can you describe them?
OH
H3C
H3C
C
H2
H2
C
H3C
C
H2
OH
H2
C OH
H3C
H3C
H2
C
H2
C
C
H2
C
H2
H2
C
OH
C
H2
OH
Homologous series: family of organic
compounds, with the functional group, but
different carbon chain length.
Homologous series:
Same general formula, e.g. CnH2n+2
Each member differs from the next by CH2
Similar chemical reactivity
Length of chain affects bp and mp
Task
• List the first 10 members of the alkanes
homologous series.
Number of
carbons
1
2
3
4
5
6
7
8
9
10
Name of
alkane
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
Stem
methethpropbutpenthexheptoctnondec-
Functional group: part of the organic molecule
responsible for its chemical properties.
Each carbon has a tetrahedral shape
with a bond angle of 109.5 o
Naming alkanes
• The longest alkane chain provides the base,
or STEM, of the name
• Additional details, like where particular
groups are, are added onto this stem
So 3-bromoheptane, is a heptane molecule
with a bromine atom attached onto the third
carbon
Different groups that can be added to
alkanes
• The simplest is the alkyl group – these are
simply smaller branches of alkanes off the
longest chain
• We can also add halogens, so chlorine atoms
are included as chloro-, bromine as bromo• Others include alcohols, carboxyl groups,
arenes and aldehydes
Adding numbers
• The number of certain groups is given with
the greek number prefix (bit before)
So dimethylbutane has 2 methyl groups
The position of each group along the main
chain is given with numbers, so
Naming branched chain molecules
1. First we find the longest chain in the molecule.
This makes the stem of the molecule
Butane
Naming branched chain molecules
1. First we find the longest chain in the molecule.
This makes the stem of the molecule
2. Then we count how many branches there are of
each kind of alkyl group. E.g. Two methyl groups
becomes dimethyl, three becomes trimethyl etc
2-Methylpentane
Naming branched chain molecules
1. First we find the longest chain in the molecule.
This makes the stem of the molecule
2. Then we count how many branches there are of
each kind of alkyl group. E.g. Two methyl groups
becomes dimethyl, three becomes trimethyl etc
3. Order the alkyl groups in alphabetical order,
ignoring the di-, tri-, tetra- info
4. Use number in front of each group to indicate
where on the chain it is.
4-Ethyl-3-methylheptane
Naming branched chain molecules
1. First we find the longest chain in the molecule.
This makes the stem of the molecule
2. Then we count how many branches there are of
each kind of alkyl group. E.g. Two methyl groups
becomes dimethyl, three becomes trimethyl etc
3. Order the alkyl groups in alphabetical order,
ignoring the di-, tri-, tetra- info
4. Use number in front of each group to indicate
where on the chain it is.
2,2-dimethylbutane
Task:
1)Draw the following molecules
a)Butane
b)2,4-dimethylpentane
c) 2-ethyl-4-methylhexane
d) 2-ethyl-3-methylbutane
e) 3-butyl-4-ethyl-5-propyldecane
Name each of the following hydrocarbons
Adding double bonds
• The number goes in front of the –ene suffix
(bit at the end)
e.g. pent-2-ene has the double bond after the
second carbon atom
But-1-ene
Task:
1)Draw the following molecules:
a)2-methylbut-2-ene
b)Hex-2-ene
2) Name the following alkenes
Practice questions
• Name the five different isomers of hexane
• Draw all of the different isomers of the
following molecules and give the systematic
names to all:
Heptane
Octane
Nonane
Naming hydrocarbons
L.O.:
 Use the terms homologous series and functional
group.
 Understand the terms hydrocarbon, saturated,
unsaturated.
 State that alkanes and cycloalkanes are saturated
hydrocarbons.
 Explain the tetrahedral shape around each carbon
atom present in an alkane.
 State the names of the first ten members of the
alkane homologous series.