IGCSE Chemistry 0620 Past Papers: How to Use Them Properly

A student who has worked through five years of 0620 papers with a mark scheme in hand will beat a student who re-read the textbook ten times. Not because past papers teach chemistry, but because they teach the 0620 examiner: the recurring question stems, the mark-scheme phrasing, the traps that reappear every series. The catch is that most students use past papers in a way that wastes most of their value.

Why past papers outrank every other revision method

Three reasons, all specific to how Cambridge writes 0620.

The question bank recycles structures. The contexts change (a different metal, a different ester), but the mark-scheme skeletons repeat. Electrolysis questions want electrode products and half-equations. Rate questions want the factor, the collision-frequency link, and the energy condition. After five years of papers you stop meeting new questions; you meet old questions in new clothes.

Mark schemes teach the only language that scores. “The bromine water goes clear” and “the bromine water turns colourless” describe the same test tube; only one earns the mark. You cannot learn creditable phrasing from a textbook, because textbooks explain. Mark schemes pay.

Timed papers expose the real failure mode. Most students who miss their grade knew the chemistry. They ran out of time on Paper 4, or wrote describe-answers under explain-questions, or misread “use data from the table”. Those errors only surface under exam conditions, which is why untimed revision feels productive and predicts nothing.

How much is enough? Four to six full years: both series, all three of your papers. That is roughly 10 sets of each component, enough to see every question structure at least twice.

The method: timed, self-marked, logged

A past paper done loosely is worth perhaps a fifth of one done properly. The proper cycle has three parts.

1. Sit it timed, closed-book

Print the paper. Set the real time limit: 45 minutes for Paper 1/2, 75 minutes for Paper 3/4, 60 minutes for Paper 6. Phone outside the room. No pausing, no peeking. The first two timed papers will feel brutal. That is the point. Better to meet the time pressure in your bedroom in week one than in the exam hall.

2. Mark it yourself against the official mark scheme

Self-marking is where the learning happens, so do not outsource it. Go answer by answer and be harsh: if your wording does not match a creditable point on the scheme, no mark. Half-right phrasing earns zero in the real hall, so it earns zero at your desk. While marking, write the scheme’s wording next to your own wherever they differ. That side-by-side comparison is the fastest phrasing lesson available, and it is exactly the drill behind our command words guide.

3. Keep an error log

One notebook page per paper, three columns:

Question	Why I lost the mark	Category
Q3(b)	wrote “amount” instead of “moles”	phrasing
Q5(c)	no units on concentration	habit
Q7(a)	could not recall test for sulfate ions	knowledge

Categorise every dropped mark as knowledge (didn’t know it), phrasing (knew it, said it uncreditable), or habit (units, sig figs, misread question). Most students discover that fewer than half their losses are knowledge gaps, which means re-reading notes, the default revision activity, attacks the minority of the problem. The log tells you what to fix; the list of common exam mistakes tells you how examiners see the same errors from their side of the desk.

Before the next paper, re-read the log. The goal is never to lose the same mark twice.

Use the examiner reports (almost nobody does)

Every series, Cambridge publishes a Principal Examiner Report for each 0620 paper. It walks through the paper question by question: what strong candidates wrote, which popular wrong answers appeared, where “the majority of candidates” confused oxidation with reduction. Reading the report for a paper you have just sat and marked is the closest you will get to a conversation with the person who graded it.

Two high-yield uses: read the report’s comments on every question where you dropped marks, and skim the general comments at the top. That is where examiners list the series-wide failures, and the same failures appear series after series.

Where to get official papers

Use official sources only. Cambridge hosts the official 0620 past papers, mark schemes and examiner reports at Cambridge International under syllabus 0620. Your school has fuller access: every Cambridge centre’s exams officer can pull the complete archive from the Cambridge support hub, and most Malaysian international schools will share sets with students who ask. Avoid re-typed papers on aggregator sites: transcription errors in data tables and equations are common enough to make a calculation unanswerable, and you will not know whether the fault is yours or the typist’s.

Want a paper walked through, line by line?

Mark schemes tell you the creditable answer; they do not show the route from question to answer. That walkthrough (the working, the mark-scheme phrasing, where each mark is awarded) is exactly what happens in a lesson. Bring any past paper you have attempted to a free 1-hour trial lesson and a Chemistry specialist will mark it the way an examiner would and show you where the marks went.

Worked exam question

Here is the past-paper cycle compressed into one real example.

Q (Paper 4 style): Explain, in terms of particles, why increasing the temperature increases the rate of reaction between zinc and dilute hydrochloric acid. (3)

Typical first-attempt answer: “The particles move faster so they react more”: 1 mark at best.

Mark-scheme answer: Particles gain kinetic energy and move faster (1); collisions occur more frequently (1); a greater proportion of collisions have energy equal to or above the activation energy (1).

What the error log records: “Knew the idea, scored 1/3, missing ‘more frequent collisions’ and the activation-energy point. Category: phrasing.” The next rate question, that student writes all three points in three lines. That single log entry is worth two marks on every future rate question, and rate questions appear on nearly every Paper 4.

The mistakes that cost marks

1. Doing papers untimed. Time pressure is half the exam. An untimed 80% predicts a timed 65%.
2. Marking generously. “That’s basically what the scheme says” is how students certify wrong answers as right. Match the creditable point or score zero.
3. Doing papers without logging. Ten papers with no error log produce the same mistakes in paper ten as paper one.
4. Starting with the most recent papers. Save the latest two series for full timed mocks in the final fortnight; burn the older years first.
5. Only doing the theory paper. Paper 2 is 30% of the grade and Paper 6 is 20%. A past-paper diet of Paper 4 alone leaves half the exam untrained.

The Malaysia note

Malaysian students sit 0620 in the May/June or October/November series, so build your paper set from both. November papers are not “backup” papers, they are half the question bank. One pattern we see in students from KL and Penang international schools: school gives plenty of papers but nobody teaches the marking step, so students grade themselves kindly and plateau. If your past-paper scores have flatlined for three weeks, the problem is usually the marking and the log, not the chemistry. That is the first thing a specialist checks in a free trial lesson.