Home > Subjects > Chemistry > Level 2 > 2.2 Volumetric analysis > Achievement criteria
- Subject: Chemistry
- AS: AS90306
- Level: 2
- Credits: 3
- Internal
Chemistry 2.2 Carry out an acid-base volumetric analysis
Achievement criteria
The criteria for each level of achievement is based on the degree of accuracy in carrying out a titration and calculate the concentration of a solution.
A higher level of accuracy is gained if you read a burette, for example, to 0.05 mL or 0.02 mL, rather than just 0.1 mL. Consequently, the average titre will then be of greater accuracy too.
Achievement
- Carry out an acid-base titration.
- Use titration data to calculate the concentration of a solution.
- At least two recorded titre values must fall within a range of 0.4 mL and the average titre value must be within 0.8 mL of the expected outcome.
- The calculation will be carried out using an appropriate procedure (which will not provided). A minor error (such as incorrect substitution of a numerical error or incorrect conversion of volumes such as mL to L) is allowed but the solution must be a sensible one. You will not be penalised for using all titre values in your calculation.
Achievement with Merit
- Carry out an acid-base titration with reasonable precision.
- Use titration data to correctly determine the concentration of a solution.
- At least three titre values must fall within a range of 0.4 mL and the average titre value must be within 0.5 mL of the expected outcome.
- A titration calculation is carried out correctly using only concordant (or consistent or similar) titre values.
Achievement with Excellence
- Carry out an acid-base titration with high precision.
- Use titration data from a reaction where the stoichiometry is not one-to-one, to correctly determine the concentration of a solution.
- At least three titre values must fall within a range of 0.2 mL; the average titre value used is within 0.2 mL of the expected outcome.
- A titration calculation where the stoichiometry is not one-to-one must be carried out correctly using only concordant (or consistent or similar) titre values. The final answer must have correct units and an appropriate number of significant figures.
