IGCSE Chemistry 0620 notes, quizzes & practice

How the kinetic particle theory explains solids, liquids and gases, what happens to particles when a substance melts, boils, condenses or freezes, and how diffusion moves particles from one place to another.

How matter is sorted into elements, compounds and mixtures, what an atom is made of, and how the arrangement of electrons explains the Periodic Table. The topic then shows how atoms join by ionic and covalent bonds, how giant covalent and metallic structures are built, and how structure and bonding decide the properties of each substance.

How to write formulae and balanced equations, work out relative atomic and molecular masses, and use the ratio in an equation to find reacting masses — then, at Extended level, how the mole links mass, gas volume and concentration so that yield and purity can be calculated.

How passing a current through a molten or dissolved ionic compound breaks it down, how to work out which product forms at each electrode, how metals are electroplated, and how a hydrogen–oxygen fuel cell makes electricity with water as its only product.

How reactions transfer energy to and from their surroundings, how a reaction pathway diagram shows the reactants, products, activation energy and overall energy change, and how the energies of the bonds broken and formed explain whether a reaction is exothermic or endothermic.

How to tell a physical change from a chemical change, what controls how fast a reaction goes, why some reactions can reverse and settle at equilibrium, and how electrons and oxygen are transferred in redox reactions.

The characteristic reactions of acids and alkalis, how indicators and the pH scale compare acidity, the difference between strong and weak acids, how oxides are classified, and the practical methods used to prepare, separate and purify soluble and insoluble salts.

How the Periodic Table organises every element by proton number, what stays the same down a group and what changes across a period, the trends and reactions of Group I and Group VII, and the special properties of the transition elements and noble gases.

The general properties and reactions of metals, why alloys beat pure metals, how the reactivity series predicts everything from displacement reactions to extraction methods, why iron rusts, and how the blast furnace and electrolysis pull metals out of their ores.

What natural water contains and how it is treated and tested, why fertilisers matter to farming, the composition of clean air, where each pollutant comes from and what it does, how greenhouse gases warm the planet, and how photosynthesis removes carbon dioxide.

The families of carbon compounds and their general formulae, how petroleum is separated into useful fuels, the reactions of alkanes and alkenes, how ethanol is made and oxidised, and how monomers join into the plastics, nylon, PET and proteins of everyday life.

Choosing the right apparatus, running a titration, reading chromatograms and calculating Rf, separating and purifying mixtures by filtration, crystallisation and distillation, and the complete set of qualitative tests for anions, cations and gases.