Required Practicals: A Skills Checklist

Most chemistry courses include a set of required or core practicals, and exam questions about them are common: describe how you would…, explain why…, suggest an improvement… Whatever syllabus you follow, the same underlying skills come up again and again. This checklist lets you rate yourself on each one, shows what a confident answer or technique looks like, and points you to a guide for anything you’re unsure of.

How to use the checklist

For each skill, give yourself a rating:

• 3 – I can do this confidently and explain why each step matters.
• 2 – I can do it, but I’m unsure of some details or reasons.
• 1 – I haven’t done this, or I’d need help.

Focus revision on your 1s and 2s. Come back in a few weeks and re-rate.

1. Working safely

Skill	What “good” looks like
Identify hazards from symbols and labels	You can name the meaning of each GHS pictogram. See hazard symbols.
Write a simple risk assessment	You state the hazard, the risk and a specific control measure (not just “be careful”). See risk assessment.
Choose the right protection	Eye protection always; gloves and a fume cupboard when the chemicals require them.
Deal with spills and breakages	You know to tell the teacher, and how small spills are neutralised or absorbed.

Exam tip: “Wear goggles” earns credit only when it’s linked to a specific hazard: “wear eye protection because sodium hydroxide is corrosive to eyes.”

2. Measuring mass

Skill	What “good” looks like
Use a top-pan balance correctly	Tare (zero) with the container on; add solid away from the balance pan; close draughts. See using a balance.
Weigh by difference	Weigh the container with solid, transfer, reweigh the container; the difference is the mass transferred.
Record to the balance’s resolution	e.g. 2.45 g on a 0.01 g balance, not 2.4 or 2.450.

3. Measuring volume

Skill	What “good” looks like
Choose the right equipment	Measuring cylinder for approximate volumes; pipette or burette for accurate ones. See measuring volume accurately.
Read a meniscus	Eye level, bottom of the meniscus for clear liquids, on a white background.
Use a pipette	Rinse with the solution, fill with a pipette filler past the mark, adjust to the mark, drain with the tip touching the flask.
Use a burette	Rinse with titrant, fill, remove air bubble from the tip, read to ±0.05 cm³.

See volumetric glassware tolerances for the uncertainties of each item.

4. Titration

Skill	What “good” looks like
Carry out rough and accurate titrations	A quick rough titre, then accurate titres adding drop by drop near the end point.
Swirl and use a white tile	The colour change is seen clearly and the end point is not overshot.
Obtain concordant results	Titres within 0.10 cm³ of each other; the mean is calculated from these only.
Choose an indicator	Matches the pH range of the steep part of the curve. See choosing an indicator.

Full walk-through: acid–base titration. Common problems: titration errors.

5. Making a standard solution

Skill	What “good” looks like
Dissolve the solid fully	Weigh, dissolve in a beaker with some distilled water, then transfer.
Transfer without loss	Rinse the beaker and glass rod into the volumetric flask several times.
Make up to the mark	Add water until the bottom of the meniscus sits on the line, dropwise at the end.
Mix	Stopper and invert the flask many times.

6. Heating safely

Skill	What “good” looks like
Choose a heat source	Water bath or electric heater for flammable liquids; Bunsen for non-flammable solutions.
Heat a test tube	Hold at an angle, pointing away from people, heating gently near the surface.
Heat to constant mass	Heat, cool, weigh; repeat until two masses agree, showing the reaction is complete. See hydrates.

7. Separating and purifying

Skill	What “good” looks like
Filtration	Folded filter paper in a funnel, wet to seat it; residue washed with small portions of cold solvent.
Evaporation and crystallisation	Heat to concentrate, then let it cool slowly so larger, purer crystals form.
Simple distillation	Thermometer bulb at the side arm; water in at the bottom of the condenser. See boiling point determination.
Paper or thin-layer chromatography	Pencil baseline above the solvent level; lid on the tank; solvent front marked immediately. See paper chromatography.
Melting point test	Sample dry and packed; heated slowly near the melting point. See melting point determination.

8. Identifying substances

Skill	What “good” looks like
Flame tests	Clean wire loop; observe colour at the edge of a blue flame. See flame test colours.
Precipitate tests	Add reagent dropwise then in excess, and state colour and what happens in excess.
Anion tests	Correct acid for each test, in the correct order. See identifying ions.

9. Measuring rates and energy changes

Skill	What “good” looks like
Collecting gas	Gas syringe or upturned measuring cylinder; readings at regular times.
Timing a reaction	Consistent end point judgement (e.g. a cross disappearing under the flask).
Measuring temperature change	Insulated cup with a lid; record the maximum (or minimum) temperature. See enthalpy of neutralisation.

10. Recording data

Skill	What “good” looks like
Design a results table	Independent variable in the first column; units in headings, not in cells.
Consistent precision	All values in a column to the same number of decimal places.
Significant figures	Calculated answers to a sensible number of significant figures. See significant figures.

11. Graphs

Skill	What “good” looks like
Axes and scale	Independent variable on the x-axis; labels with units; scale uses more than half the grid.
Plotting	Points plotted accurately as small crosses.
Line of best fit	A smooth line or curve with points balanced either side; anomalies ignored and identified.
Gradients and intercepts	A large triangle used for the gradient; units stated.

See graphs in chemistry.

12. Evaluating

Skill	What “good” looks like
Identify variables	Independent, dependent and control variables stated. See variables.
Spot anomalies	Values that don’t fit the pattern are identified, with a possible reason.
Calculate percentage uncertainty	Uncertainty ÷ measured value × 100. See calculating uncertainty.
Suggest specific improvements	e.g. “use a burette instead of a measuring cylinder to reduce the percentage uncertainty”, not “be more careful”.

Turning the checklist into a plan

1. List every skill rated 1 or 2.
2. For each, read the linked guide and write the method from memory in five steps or fewer.
3. Ask your teacher if you can repeat or watch the practical.
4. Practise exam-style “describe” and “evaluate” questions; write the answer, then compare with the guide.
5. Write up at least one practical in full as a lab report.

Key takeaways

• The same core skills underpin all required practicals: safety, measurement, technique, recording and evaluation.
• Rate yourself honestly and focus on your weakest skills.
• Exam answers need specific equipment, specific steps and specific reasons.
• Improvements should name a change and explain how it reduces error or uncertainty.