How to score on IGCSE Chemistry Paper 6: the 40-mark practical paper (20% of the grade), skill by skill in one table
Paper 6 is the written practical paper: no lab, but every question assumes you have done the experiment. The good news is that the same skills come up every series, so targeted practice pays off fast. This guide puts each skill in a table, with what scores and what loses marks, and lets you read a burette the way the exam asks.
The short answer
Paper 6: Alternative to Practical lasts 1 hour, is worth 40 marks and makes up 20% of the IGCSE Chemistry (0620) grade. Candidates sit either Paper 6 or Paper 5, the practical test in a lab.
20% is 40 of the 200 weighted marks, and the grade C threshold in June 2026 (22/42/62) was 80. Paper 6 alone is worth half a grade C.
Why most home-school and private candidates sit Paper 6 is covered in the home lab guide. This one is about scoring.
What Paper 6 asks: one table
The paper gives you apparatus diagrams, results tables or graphs and tests the same skills every series. This table covers all 9. The green column is what the examiner wants; the red one is where students usually lose marks.
Tap a row to highlight it
Reading apparatus in a diagram
Scores whenRecords to the scale's precision: burettes to 2 d.p. (ending .00 or .05), with units
Usually loses marks byRounding, e.g. 23.4 instead of 23.40, or reading a burette bottom-up
Results tables
Scores whenHeadings give the quantity and unit; one column, one number of decimal places
Usually loses marks byUnits in every cell instead of the heading, or mixed decimal places
Plotting graphs
Scores whenLabelled axes with units, scale over half the grid, points within half a square, one straight line or smooth curve
Usually loses marks byDot-to-dot zigzags, awkward scales such as 3 squares per unit
Variables
Scores whenNames a measurable quantity: temperature of the acid, volume of gas
Usually loses marks byVague answers: the amount, the acid
Errors and improvements
Scores whenNames a problem specific to this experiment and the fix that matches it
Usually loses marks byGeneric answers: human error, be more careful
Conclusions
Scores whenQuotes the trend or numbers from the given table or graph
Usually loses marks byConcluding more than the data shows
Naming apparatus
Scores whenExact names: pipette, burette, conical flask, gas syringe, measuring cylinder
Usually loses marks byLoose names: tube, glass, cup
Tests for ions and gases
Scores whenGives the reagent and what is seen (colour, precipitate, bubbles)
Usually loses marks byNaming the product instead of what is seen
Planning an experiment
Scores whenComplete steps: apparatus, amounts, what is measured, what is kept the same, repeats, how to conclude
Usually loses marks byToo short; never says what is measured or how the result is decided
Reading apparatus: the easiest marks, and the easiest to drop
Reading marks need no chemistry at all, only two things: read in the right direction, and record to the precision the scale allows. Pick the value that scores below.
Pick the value that scores
1. What should be recorded for this burette?
2. Initial reading 1.20 cm³, final reading 24.35 cm³. What is the titre?
3. What should be recorded for this thermometer?
"Suggest an improvement": answer the actual problem
The question describes a problem with the experiment and asks how to fix it. The answer that scores fixes that problem directly. A generic answer like be more careful scores nothing, whatever the question.
Keep this pair straight: more reliable = repeat and take a mean; more accurate = use apparatus that measures more precisely, or cut a loss such as heat.
Tap a row to highlight it
Heat is lost while measuring temperature
Answer that scoresUse a polystyrene cup with a lid (insulate the container).
Answer that does notUse a better thermometer.
A measuring cylinder is not precise enough
Answer that scoresUse a pipette (or a burette) to measure the volume.
Answer that does notMeasure more carefully.
The end-point is hard to see
Answer that scoresPut the flask on a white tile; add the acid dropwise near the end-point while swirling.
Answer that does notLook more closely at the colour.
The experiment was done only once
Answer that scoresRepeat the experiment and calculate a mean (ignore anomalous results).
Answer that does notUse more accurate equipment.
Crystals were weighed while still wet
Answer that scoresDry the crystals and heat to constant mass before weighing.
Answer that does notWeigh it again.
Chromatography: start line drawn in pen
Answer that scoresDraw the start line in pencil, above the level of the solvent.
Answer that does notDraw the line more neatly.
How to practise Paper 6
Do past papers timed at 1 hour, use a sharp pencil and a ruler for every graph, and mark yourself against the mark scheme point by point.
After every graph, check four things: labelled axes with units, a scale using over half the grid, accurate points, one smooth line.
Learn the tests for ions and gases until they are automatic; they score on Papers 2, 4 and 6.
Write planning answers as numbered steps with numbers in them: which apparatus, how much, what you measure, what you keep the same, repeats, and how you decide the result.
Where Boom-Tutor helps
Every unit in the course is an on-screen experiment the student runs in the same order as a Paper 6 question: predict, run it, read the apparatus, record the results in a table, then write the observation and explanation for AI to mark against the marking points.
One full unit is free, no sign-up: the NH₃ and HCl diffusion tube. The self-learn course is ฿4,900, paid once, with access until the exam session. The platform is expected to open around December 2026.
Try: all 12 IGCSE Chemistry topics, interactive, on one page
Stuck on something the AI explanation did not fix? Book a lesson with Boom.