Paper 6 Practical Skills
Read apparatus, record evidence and explain your experimental decisions. Revisit these skills alongside your chemistry chapters.
The examination lasts one hour and carries 40 marks. Qualitative analysis notes are provided. These activities support classroom practical experience.
Guided worksheet
Five modules with teacher models, independent tasks and partner checks.
Download DOCX ↓40 mark practice paper
Original classroom questions. Allow 60 minutes or practise one section at a time.
Download DOCX ↓Hint cards
Paper 6 cards are on pages 7–9. Use them during learning, then try without support.
Download DOCX ↓Apparatus and measurements
Select apparatus, read scales and calculate delivered volumes.
- Paper 6 asks you to use experimental evidence. It is a one-hour, 40-mark alternative-to-practical paper.
- A pipette delivers a fixed accurate volume. A burette delivers a measured variable volume. A measuring cylinder gives less precise volume measurements.
- The scale increases downwards. Read the bottom of a clear solution’s meniscus at eye level.
- A rough titration locates the endpoint. Repeat accurate titrations and use consistent results according to the question’s criterion.
Quick check
Why is the final burette reading alone not always the titre?
Check after attempting
The starting reading may be above zero. The titre is the difference.
Separation and salt preparation
Explain a method using the properties of the substances involved.
- Filtration separates an insoluble solid from a liquid. Crystallisation recovers a dissolved solid.
- Warm dilute acid and add the suitable insoluble base in small portions until some solid remains. Filter off the excess.
- Draw the baseline in pencil and keep it above the solvent. Mark the solvent front before it evaporates.
- A gas syringe measures gas volume. Collection over water is suitable only if the gas is sufficiently insoluble and does not react with water.
Quick check
Why can filtration alone not separate dissolved salt from water?
Check after attempting
The dissolved ions pass through the filter with the water.
Observations and qualitative analysis
Use the supplied analysis notes to select tests and justify identities.
- Write a visible observation: “a light blue precipitate forms”. Then infer an ion by comparing the notes.
- With aqueous ammonia, Cu²⁺ gives a light blue precipitate that dissolves in excess to form a dark blue solution.
- For halides, acidify with dilute nitric acid and add silver nitrate: chloride white, bromide cream, iodide yellow.
- Hydrogen pops with a lighted splint. Oxygen relights a glowing splint. Carbon dioxide turns limewater milky.
Quick check
Why should hydrochloric acid not be used to acidify a chloride test?
Check after attempting
It introduces chloride ions and can cause a misleading positive result.
Tables graphs and evaluation
Process data, identify anomalous results and link improvements to errors.
- Illustrative data: a fixed mass of magnesium reacts with excess acid. A gas syringe measures hydrogen every 20 s.
- Put time on the horizontal axis and volume on the vertical axis. Label quantities and units and choose an even scale.
- Average rate over an interval = change in volume / change in time. A tangent estimates the rate at an instant.
- A leak loses gas and makes measured volume too low. Check the bung and connections before starting.
Quick check
Will repeating a leaking gas-collection experiment automatically make the result accurate?
Check after attempting
No. Repair the leak. Repeats can reveal variability but do not remove systematic loss.
Planning an investigation
Write a reproducible plan with variables, measurements and data processing.
- State what you change and what you measure. Give a sensible range and units. Keep relevant quantities constant.
- In a solution model, change one quantity at a time. Distinguish the amount dissolved from how quickly a solid dissolves.
- A suitable classroom planning context is magnesium reacting with excess dilute acid. Compare fixed temperatures using a water bath.
- Specify a hazard and matching precaution: dilute acid can irritate eyes, so wear eye protection. Hydrogen is flammable, so exclude ignition sources.
Quick check
What is wrong with “change the acid and see what happens”?
Check after attempting
It lacks a defined variable, measurements, controlled quantities and a reproducible method.
Burette reading practice
Read the bottom of each meniscus. Each small division is 0.1 cm³. Estimate to the nearest half division and calculate final minus initial.
Scale-reading model only. Practise filling, rinsing, clamping and recognising endpoints with your teacher’s approved apparatus procedure.