IGCSE Chemistry (Cambridge 0620) is a rigorous and rewarding qualification that tests both theoretical knowledge and practical skills. For students aiming at an A*, it requires careful topic coverage, strong exam technique across all three papers, and genuine engagement with practical chemistry. This guide walks you through everything you need to know.
Understanding the IGCSE Chemistry Syllabus
Cambridge IGCSE Chemistry 0620 is divided into Core content (covered by both Core and Extended candidates) and Supplement content (Extended candidates only). If you are sitting the Extended papers (which allow you to achieve A*โE), you must cover both Core and Supplement topics. The Extended content is typically 20โ30% more material and involves more complex calculation and application questions.
Topic-by-Topic Breakdown
1. Particulate Nature of Matter & Atomic Structure
Start here. Everything in chemistry builds on an understanding of atoms, ions, molecules, and their structure. Ensure you can draw Bohr model diagrams, write electronic configurations, and explain ionic and covalent bonding. Common exam questions ask you to explain properties (e.g., electrical conductivity, melting point) in terms of structure and bonding โ prepare a standard framework answer for each type of structure.
2. Stoichiometry
Mole calculations are the mathematical backbone of IGCSE Chemistry. Practice is the only way to become fluent. Master these calculations: moles from mass (n = m/M), moles from gas volume (n = V/24 at RTP), concentration calculations (c = n/V), limiting reagent problems, and percentage yield. These appear in almost every exam.
3. Acids, Bases, and Salts
This topic is high-mark and relatively predictable. Learn the definitions of acid, base, and alkali precisely. Know the pH scale, indicators, and the products of neutralisation. Practise writing salt preparation methods (direct combination, displacement, neutralisation, precipitation) and the ionic equations for each. The Extended syllabus also requires knowledge of buffer solutions.
4. Electrochemistry
Electrolysis questions are frequently poorly answered because students are imprecise about electrode products. The rules: at the cathode (negative electrode), cations are reduced and metal deposits or hydrogen gas is produced depending on concentration and position in the reactivity series. At the anode (positive electrode), anions are oxidised; chlorine gas is produced in concentrated chloride solutions, oxygen in dilute solutions.
5. Organic Chemistry
Organic chemistry has a large number of named reactions and functional group tests that must be memorised. Create a table: functional group, test reagent, positive result. For each reaction type (addition, substitution, esterification, polymerisation), know the reactants, conditions (temperature, catalyst), and products. Nomenclature (naming organic compounds) is tested regularly โ practise IUPAC naming for alkanes, alkenes, alcohols, and carboxylic acids.
- โขAlkanes: saturated, substitution reactions with halogens (UV light), combustion.
- โขAlkenes: unsaturated, addition reactions (HBr, water, Brโ), polymerisation, bromine water test (decolourise).
- โขAlcohols: oxidation to carboxylic acids, esterification, combustion, test with sodium (fizzing).
- โขCarboxylic acids: weak acids, esterification with alcohols, react with carbonates and metals.
Paper Strategy
Paper 1: Multiple Choice
Paper 1 is 45 minutes and consists of 40 multiple choice questions worth 1 mark each. It covers Core content only. There is no negative marking, so attempt every question. Common traps include questions that test very specific definitions (especially acid/base), ionic equations, and element identification from electronic configuration.
Paper 2: Core Structured Questions
Paper 2 is 1 hour 15 minutes and assesses Core content with structured, short-answer questions. Questions follow a predictable format: describe observations, write balanced equations, explain in terms of particles. Practice answering questions using the mark scheme's expected phrases. Vague answers rarely earn full marks.
Paper 3: Extended Structured Questions
Paper 3 is the Extended paper (1 hour 15 minutes) and tests both Core and Supplement content. It includes calculation questions worth 2โ6 marks. Show all working for calculations โ method marks are awarded even if the final answer is incorrect. Extended questions often ask you to 'explain' or 'suggest' โ these require chains of reasoning, not single-word answers.
Practical Skills
Even without a separate practical paper, IGCSE Chemistry exams include questions on experimental design, results analysis, and evaluation. You will be asked to suggest a method to test for a specific substance, describe how to improve an experiment's accuracy, or explain why results might be anomalous. Familiarise yourself with common lab techniques: filtration, crystallisation, distillation, titration, and chromatography.
8-Week Revision Plan for IGCSE Chemistry
- 1.Week 1: Atomic structure, bonding, and structure/properties.
- 2.Week 2: Stoichiometry โ mole calculations, equations, limiting reagents.
- 3.Week 3: Acids, bases, salts โ salt preparation and ionic equations.
- 4.Week 4: Electrochemistry and redox.
- 5.Week 5: Organic chemistry โ all functional groups and reactions.
- 6.Week 6: Energy, rates of reaction, and reversible reactions.
- 7.Week 7: Past paper practice โ Paper 2 and Paper 3 under timed conditions.
- 8.Week 8: Targeted revision on weak topics identified from past papers.
"IGCSE Chemistry rewards precision above all. A student who gives precise, specific answers โ with correct chemical terminology โ will always outscore a student who writes vague, general responses, even if both understand the concept."
โ Ashish Pachar, PhyFix Founder