Pearson International A Level Chemistry Unit 6: Practical Skills II
Pearson IAL Chemistry practical notes on advanced experimental procedures and techniques developed through Units 4 and 5.
This paper does not require a separate hands-on examination. It assesses practical knowledge and reasoning in writing. Unit 6 draws on the relevant theory units and expects candidates to plan, record, process, conclude and evaluate in both familiar and unfamiliar contexts.
Aim and scientific principle
Turn a scientific question into measurable variables, a controlled comparison and an analysis that can answer the stated aim.
Begin by translating the title into a testable question. Identify what is deliberately changed, what is measured directly, what is calculated and what must remain controlled. Predict a relationship only after naming the mechanism. A prediction without a reason is weak; a reason without measurable variables cannot guide a practical design.
Apparatus and setup
Use appropriate measuring instruments, labelled containers or supports, a timer where needed, and equipment selected for suitable range and resolution. Select every measuring instrument by range and resolution, not by name alone. Draw a labelled scientific setup that shows the working geometry and exactly where readings are taken. Include a control or blank when it distinguishes the target effect from drift, contamination or background response.
Before collecting results, check zero readings, calibration, leaks, alignment or sterility as relevant. Record the instrument resolution beside the first raw-data table. If a digital device displays more digits than its underlying accuracy supports, do not treat every digit as equally certain.
Method
- Define the independent and dependent variables operationally before collecting data.
- Choose a sensible range with enough values to reveal the expected relationship.
- Control relevant factors, take repeat readings and record raw data with units and instrument precision.
- Process the results using the specified calculation or graph, then evaluate uncertainty, anomalies and limitations.
Plan the analysis before starting. This reveals whether an additional measurement is needed for a derived quantity and prevents a completed experiment from lacking a mass, length, concentration, background or calibration value. A method should be detailed enough for another trained student to reproduce, while avoiding decorative steps that do not affect validity.
Variables and controls
- Independent variable: the factor deliberately changed across a planned range.
- Dependent variable: the directly measured response and any derived quantity.
Check this topic from memory
Attempt the matching topic bank before reopening the notes. Use each missed idea to decide what to review next.
Start the topic quiz