CPAC General Guide
This is a brief guide designed to ensure that students pass their CPACs. Many students do
not pass their skills the first time and have to resort to extra practicals towards the end of
year 13 which is unnecessary added stress. By following each of these steps in this guide
you will be able to pass each skill tested.
These sections should be included in your write-ups. The tasks indicated in italics, on the
other hand, are reserved for when you are being evaluated on that particular talent.
1) Brief introduction: State what is the aim of the practical, possibly including research
about specific things asked (this step is not compulsory however it is helpful if
referencing is required)
2) State your variables
● Independent variable and how will be changed/controlled to ensure accuracy
● Dependent variable and how will be measured accurately
● Control variables: include the following table and have at least 3 variables
Control Variable How will it be controlled? Will it be difficult to control
and how could this affect
your results?
3) Make sure you explain the justification behind the necessity of each piece of
equipment and the reason(s) for selecting particular-sized measuring cylinders in
relation to accuracy (you may need to calculate percentage uncertainty)
4) Detailed and amended method - include justifications under each step and any
modifications made obvious
Example: Add 1cm3 of ethanol (2cm3 were used instead as the reagents were not mixing
well) to the reaction mixture using a measuring cylinder
The non-polar solvent ethanol helps the organic reagents to mix so the reagent
particles can collide and react
5) Risk assessment - Use this table
Hazard (consider reactants, Risk (low or high?) Precaution (including
products and procedures) method of disposal)
This is a brief guide designed to ensure that students pass their CPACs. Many students do
not pass their skills the first time and have to resort to extra practicals towards the end of
year 13 which is unnecessary added stress. By following each of these steps in this guide
you will be able to pass each skill tested.
These sections should be included in your write-ups. The tasks indicated in italics, on the
other hand, are reserved for when you are being evaluated on that particular talent.
1) Brief introduction: State what is the aim of the practical, possibly including research
about specific things asked (this step is not compulsory however it is helpful if
referencing is required)
2) State your variables
● Independent variable and how will be changed/controlled to ensure accuracy
● Dependent variable and how will be measured accurately
● Control variables: include the following table and have at least 3 variables
Control Variable How will it be controlled? Will it be difficult to control
and how could this affect
your results?
3) Make sure you explain the justification behind the necessity of each piece of
equipment and the reason(s) for selecting particular-sized measuring cylinders in
relation to accuracy (you may need to calculate percentage uncertainty)
4) Detailed and amended method - include justifications under each step and any
modifications made obvious
Example: Add 1cm3 of ethanol (2cm3 were used instead as the reagents were not mixing
well) to the reaction mixture using a measuring cylinder
The non-polar solvent ethanol helps the organic reagents to mix so the reagent
particles can collide and react
5) Risk assessment - Use this table
Hazard (consider reactants, Risk (low or high?) Precaution (including
products and procedures) method of disposal)
