IAL CHEMISTRY- AS
ORGANIC CHEMISTRY – ALKANES
REVISION GUIDE
Q1. Give two characteristics of a homologous series
• have a common general formula
• differ by a CH2 unit
• show a trend in physical properties, for example boiling temperature
• show similar chemical properties since all members of the same homologous
Q5. Draw the skeletal formula of butan-2-ol
series have the same functional group
Hint: the carbon chain skeleton is shown by zigzag lines, where each end
Q2. What is meant by a functional group?
of a line and each angle represents a carbon atom. Hydrogens attached to
A functional group is a small group of atoms or perhaps a single atom that
other atoms should be shown
determines the chemistry of a molecule.
Q3 . Identify the functional groups in
CH3CH(OH)CH2CH=CH2.
A secondary alcohol and an alkene
Drawing organic molecules
(1) Molecular formula :shows the total number and kinds of atoms in Q6.Draw the skeletal formula of
a molecule, but not their structural arrangement. (a) pent-2-ene;
For example, the molecular formula of ethanoic acid is C2H4O2
(2) Structural formula: an unambiguous formula that shows the relative (b) 2-methylprop-2-ene.
positions of the atoms in a molecule. Side chains are enclosed in brackets.
• The structural formula of propane is CH3CH2CH3
• and that of propan-2-ol is CH3CH(OH)CH3.
• It is advisable to show any double bonds, so the structural
formula of ethene is best written as H2C=CH2.
Q4. Draw the displayed formula of butan-2-ol
Exam hint: shows all the atoms and all the bonds.
Page 1 of 7
ORGANIC CHEMISTRY – ALKANES
REVISION GUIDE
Q1. Give two characteristics of a homologous series
• have a common general formula
• differ by a CH2 unit
• show a trend in physical properties, for example boiling temperature
• show similar chemical properties since all members of the same homologous
Q5. Draw the skeletal formula of butan-2-ol
series have the same functional group
Hint: the carbon chain skeleton is shown by zigzag lines, where each end
Q2. What is meant by a functional group?
of a line and each angle represents a carbon atom. Hydrogens attached to
A functional group is a small group of atoms or perhaps a single atom that
other atoms should be shown
determines the chemistry of a molecule.
Q3 . Identify the functional groups in
CH3CH(OH)CH2CH=CH2.
A secondary alcohol and an alkene
Drawing organic molecules
(1) Molecular formula :shows the total number and kinds of atoms in Q6.Draw the skeletal formula of
a molecule, but not their structural arrangement. (a) pent-2-ene;
For example, the molecular formula of ethanoic acid is C2H4O2
(2) Structural formula: an unambiguous formula that shows the relative (b) 2-methylprop-2-ene.
positions of the atoms in a molecule. Side chains are enclosed in brackets.
• The structural formula of propane is CH3CH2CH3
• and that of propan-2-ol is CH3CH(OH)CH3.
• It is advisable to show any double bonds, so the structural
formula of ethene is best written as H2C=CH2.
Q4. Draw the displayed formula of butan-2-ol
Exam hint: shows all the atoms and all the bonds.
Page 1 of 7
