Is IGCSE Chemistry Hard? An Honest Answer

Yes. IGCSE Chemistry is harder than most subjects on a Malaysian international-school timetable, and pretending otherwise helps nobody. But “hard” is not evenly spread. Roughly four areas generate the bulk of the dropped marks, and a student who names them early and attacks them deliberately finds the rest of the syllabus surprisingly tame. Here is the honest map.

Why chemistry is genuinely harder

Abstract models you cannot see. Biology shows you a cell under a microscope; physics shows you a trolley on a ramp. Chemistry asks you to explain a fizzing test tube using particles, electrons and bonds (entities you will never observe), and 0620 awards explain-marks only at that invisible level. “The acid gets used up” scores nothing; “hydrogen ions are reduced at the magnesium surface” scores. The translation between what you see and what earns marks is a skill in itself.

Maths inside a science. Moles, concentrations, percentage yield, bond energies: 15-20% of an Extended theory paper is calculation. The maths is simple (ratio and rearrangement), but it arrives dressed in unfamiliar units (mol/dm³) and multi-step chains where one early slip poisons the final answer.

Three exam components. Your grade is built from a multiple-choice paper (30%), a structured theory paper (50%), and a practical or alternative-to-practical paper (20%). Each rewards a different skill (speed and elimination, mark-scheme phrasing, and experimental reasoning), so revising one paper style leaves half the grade untrained.

The recall load. Every ion test with its exact colours, every gas test, the reactivity series, electrode rules, the organic functional groups and their reactions. The list of pure-memory facts in 0620 is longer than IGCSE Physics’ formula sheet by a wide margin, and the mark scheme accepts no approximations: a sulfate test answer without “barium” and “white precipitate” scores zero.

The 4 areas where the difficulty concentrates

1. Moles and stoichiometry

The single biggest mark-loser on theory papers. Not because the concept is deep, but because it chains: formula to Mr, Mr to moles, moles to ratio, ratio to mass or volume or concentration: four steps, each able to kill the answer. Students who learn a fixed written layout stop bleeding marks here within weeks; the topic and its method live at stoichiometry.

2. Electrolysis

The most counterintuitive topic in the syllabus. Current flows, ions migrate, products appear at electrodes, and which product appears depends on the electrolyte, its concentration, and the reactivity series, all at once. Examiner reports flag wrong electrode products every single series. The decision rules are finite and learnable; they are laid out under electrochemistry.

3. Organic chemistry

A different language bolted onto the back of the course: homologous series, naming rules, functional groups, addition versus substitution, polymers. It usually arrives late in Form 4 or in Form 5, when students are tired, and it is tested heavily on Extended papers. Students who treat it as vocabulary plus a handful of reaction patterns, rather than 9 separate subtopics, find it the fastest of the four to fix. Start at organic chemistry.

4. Paper 6 (alternative to practical)

20% of the grade, and the paper nobody teaches. Schools run through the theory syllabus and assume practical skills absorb themselves; then Paper 6 asks students to plan an experiment, spot the anomalous result, and justify why the second titre is more reliable. The question types repeat so consistently that a focused fortnight moves this paper more than a month moves any other.

Notice what is not on this list: the periodic table, acids and salts, metals, environmental chemistry: the bulk of the syllabus, where most students cruise. “Chemistry is hard” almost always decodes to “two or three of these four are broken”.

Chemistry vs Physics vs Biology: a fair comparison

	Maths load	Recall load	Abstract models	Practical paper
Chemistry	Medium (calculations chain)	High (tests, colours, rules)	High (particles, electrons)	Yes, 20%
Physics	High (formulae throughout)	Low-medium	Medium (forces, fields)	Yes, 20%
Biology	Low	Very high (terms, processes)	Low-medium	Yes, 20%

The honest reading: Physics is harder for weak mathematicians, Biology is heavier for weak memorisers, and Chemistry demands a working level of both at once. That double demand, not any single topic, is why chemistry produces the widest grade spread of the three sciences in most school cohorts. It is also why it responds so well to targeted help: fixing one weak half lifts the whole subject.

Who finds it hard, and who doesn’t

Students who struggle usually share one of three profiles: the memoriser who hits a wall at moles, the mathematician who resents the recall load and skips ion tests, or the capable-but-late starter facing organic chemistry and Paper 6 with one term left. Students who find 0620 manageable are rarely geniuses. They are students who practised calculations to a fixed layout, learned the recall lists deliberately, and met past papers early.

For Core versus Extended, “hard” means different things. Core removes the Supplement content (the most abstract material, like bond energy calculations and oxidation numbers), and its grade ceiling is C. Extended includes everything and opens A* to B. A student choosing routes should weigh the ceiling against the workload honestly; the full decision framework is in Core vs Extended.

Worked exam question

Here is the difficulty in miniature: one Extended question crossing two of the four hard areas.

Q (Paper 4 style): Molten lead(II) bromide is electrolysed with inert electrodes. (a) Predict the product at each electrode. (2) (b) Calculate the mass of lead produced when 0.40 mol of electrons is transferred. (Pb = 207) (2)

Model answer: (a) Cathode: lead (1). Anode: bromine (1). (b) Pb2+ + 2e⁻ → Pb, so 0.40 mol electrons produces 0.40 ÷ 2 = 0.20 mol Pb (1); mass = 0.20 × 207 = 41.4 g (1).

Mark-scheme logic: (a) is the electrolysis rule for a molten binary compound: metal at the cathode, non-metal at the anode. (b) is a mole chain hiding inside an electrochemistry question: half-equation, ratio, mass. A student weak in either area scores half; weak in both, zero. This stacking of hard areas inside single questions is exactly why the four are worth fixing first.

The mistakes that cost marks

1. Calling the whole subject hard and revising everything equally. The losses are concentrated; the revision should be too.
2. Avoiding the four hard areas because they feel bad. They are 30-40% of the available marks on an Extended series. Comfort-revising the periodic table cannot compensate.
3. Treating Paper 6 as optional. A student averaging 80% on theory and 50% on Paper 6 has already spent their A* margin.
4. Switching to Core to escape difficulty without checking the ceiling. If A Level sciences are the plan, the C cap creates a bigger problem than the Supplement content ever was.

The Malaysia note

In Malaysian international schools, chemistry’s reputation is partly a scheduling artefact: organic chemistry and serious past-paper work land in the same crowded final year as every other subject’s exam preparation, so the hardest material meets the least available time. Parents comparing with their own SPM memories should note 0620 is structured differently: the practical component is examined on paper, and the mark schemes reward phrasing, not essays. If you want a precise answer to “is it hard for my child”, one diagnostic hour beats any article: a free trial lesson with a Chemistry specialist will name which of the four areas (if any) are actually in the way, and how far the target grade really is.