Home > Subjects > Chemistry > Level 3 > 3.2 Titration > Achievement criteria
- Subject: Chemistry
- AS: AS90695
- Level: 3
- Credits: 2
- Internal
Chemistry 3.2 Determine the concentration of an oxidant or reductant by titration
Achievement criteria
The criteria for each level of achievement is based on the precision or degree of accuracy in carrying out an acid-base titration and in calculating the composition of an unknown sample.
Achievement
- Carry out an oxidation-reduction titration with limited precision. This means that:
- at least two recorded titre values must fall within a range of 0.6 mL
- the average titre value must be within 0.6 mL of the expected outcome.
- Calculate the concentration of the solution analysed in a titration. This means that:
- your calculation will require using only titre values within a range of 0.6 mL to calculate the average volume
- the calculation of the concentration of the unknown solution must be carried out using an appropriate procedure (that will not be provided)
- only a minor numerical error is allowed.
Achievement with Merit
- Carry out an oxidation-reduction titration with reasonable precision. This means that:
- at least three recorded titre values must fall within a range of 0.4 mL
- the average titre value must be within 0.4 mL of the expected outcome.
- Determine the composition of the sample being analysed. This means that:
- your calculation will use only titre values within a range of 0.4 mL to calculate the average volume
- you follow a correct procedure to determine the composition of the sample.
Achievement with Excellence
- Carry out an oxidation-reduction titration with high precision. This means that:
- at least three recorded titre values must fall within a range of 0.2 mL
- the average titre value must be within 0.2 mL of the expected outcome.
- Accurately calculate the composition of the sample. This means that you will:
- calculate the average volume using only titre values within a range of 0.2 mL
- correctly determine the composition of the sample, using correct units and appropriate number of significant figures
- show evidence of being able to carry out calculations involving reactions where the reactants are not in a 1:1 mole ratio.
