Nomenclature

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Nomenclature

• L.O.
• Name simple hydrocarbons.
• Draw the structural formula from a given
  hydrocarbon name.

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Starter questions

• 1. What is a hydrocarbon?
• 2. Draw and name these molecules
• CH4
• C2H6
• C2H4
• C2H2
• C2H5OH
• C2H5Br
• C2H3 OOH
• 3. What families, or groups of hydrocarbons do
  each of these belong to?

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• Hydrocarbons are organic compounds hat contain
  carbon and hydrogen only.

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• Saturated hydrocarbon single bonds only
• Unsaturated hydrocarbon multiple
  carbon-to-carbon bonds
• Aliphatic hydrocarbon carbon atoms joined
  together in straight or branched chains.
• Alicyclic hydrocarbon carbon atoms joined in a
  ring structure.

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• This compounds belong to the same family. How can
  you describe them?

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• Homologous series family of organic compounds,
  with the functional group, but different carbon
  chain length.

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• Homologous series
• Same general formula, e.g. CnH2n2
• Each member differs from the next by CH2
• Similar chemical reactivity
• Length of chain affects bp and mp

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Task

• List the first 10 members of the alkanes
  homologous series.

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Number of carbons Name of alkane Stem
1 Methane meth-
2 Ethane eth-
3 Propane prop-
4 Butane but-
5 Pentane pent-
6 Hexane hex-
7 Heptane hept-
8 Octane oct-
9 Nonane non-
10 Decane dec-
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• Functional group part of the organic molecule
  responsible for its chemical properties.

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Each carbon has a tetrahedral shape with a bond
angle of 109.5 o
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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

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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

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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

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Naming branched chain molecules

1. First we find the longest chain in the molecule.
   This makes the stem of the molecule

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• Butane

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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

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2-Methylpentane
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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.

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4-Ethyl-3-methylheptane
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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.

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2,2-dimethylbutane
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• Task
• Draw the following molecules
• Butane
• 2,4-dimethylpentane
• 2-ethyl-4-methylhexane
• 2-ethyl-3-methylbutane
• 3-butyl-4-ethyl-5-propyldecane

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Name each of the following hydrocarbons
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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

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But-1-ene
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• Task
• Draw the following molecules
• 2-methylbut-2-ene
• Hex-2-ene
• 2) Name the following alkenes

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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

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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.