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Topic 1: Physical chemistry
1.1 Atomic structure
3.1.1.1 - Fundamental ParticlesChemists did not discover the structure of the atom in one step. The model changed as new evidence appeared, and each new model explained observations better than the one before it. In this lesson, you will learn how atomic ideas developed, what the three fundamental particles are, and how they a...
3.1.1.2 - Mass Number and IsotopesThis lesson links simple atomic structure to one of chemistry's most useful analytical tools. Particle counts, isotope notation, and mass spectra are different ways of describing the same atoms, so the ideas make most sense when you connect them. By the end, you should be able to explain isotopes...
3.1.1.3 - Electron ConfigurationElectron configurations let us describe exactly where electrons are in an atom, while ionisation energy data lets us test whether that description makes sense. In this lesson, you will build electron configurations for atoms and ions up to krypton and then use first and successive ionisation ener...
1.2 Amount of substance
3.1.2.1 - Relative Atomic Mass and Relative Molecular MassChemists do not usually work with the actual masses of individual atoms and molecules because those masses are far too small to handle conveniently. Instead, they compare particles against a fixed standard and use relative values. In this lesson, you will learn exactly what Ar and Mr mean, why ca...
3.1.2.2 - The Mole and the Avogadro ConstantChemists cannot count atoms, ions, or molecules one by one, so they use the mole as a counting unit. This lesson shows how the mole links mass, number of particles, concentration in solution, and the ratios in chemical equations. By the end, you should be able to move confidently between these id...
3.1.2.3 - The Ideal Gas EquationThe ideal gas equation links together four measurable properties of a gas: pressure, volume, temperature, and amount of substance. It turns a gas sample into something you can calculate with, provided each value is written in the correct unit. This lesson focuses on using pV = nRT accurately, wit...
3.1.2.4 - Empirical and Molecular FormulaWhen chemists know how much of each element is present in a substance, they can work backwards to its formula. That turns a list of masses or percentages into a genuine clue about what the substance is. In this lesson, you will learn how to turn composition data into an empirical formula, then ho...
3.1.2.5 - Balanced Equations and Associated CalculationsEvery chemical calculation in this topic starts with one idea: a balanced equation tells you the exact mole ratio in which particles react. If the equation is wrong, every mass, gas volume, concentration, yield, and atom economy answer built from it will also be wrong. In this lesson, you will le...
RP01 - Make Up a Volumetric Solution and Carry Out a Simple Acid-Base TitrationThis required practical is about making concentration data trustworthy. First you prepare a solution with an accurately known concentration, then you use that solution in a titration to find the concentration of another acid or alkali. To do that confidently, you need more than a recipe: you need...
1.3 Bonding
3.1.3.1 - Ionic BondingIonic bonding explains how metals and non-metals form compounds by making ions, and how those ions are held together in a giant structure. In this lesson, you will build the particle model first, then use it to predict ion charges and construct correct formulae for ionic compounds, including ones...
3.1.3.2 - Nature of Covalent and Dative Covalent BondsCovalent bonding is really about electron pairs: who is sharing them, how many pairs are shared, and how we represent that clearly on paper. Once that idea is secure, every line and every arrow starts to carry real meaning rather than just looking like notation. In this lesson, we will build that...
3.1.3.3 - Metallic BondingMetallic bonding explains why a piece of metal behaves as one joined-up structure rather than a pile of separate atoms. In this lesson, the focus stays tightly on the model itself: positive ions arranged in a lattice, delocalised electrons, and the attraction between them. By the end, you should...
3.1.3.4 - Bonding and Physical PropertiesBonding determines how particles are arranged in a solid, and that arrangement controls what happens when you heat the substance or try to make it conduct electricity. In this lesson, you will compare the four crystal structures in the specification using sodium chloride, magnesium, iodine, ice,...
3.1.3.5 - Shapes of Simple Molecules and IonsThe shape of a simple molecule or ion is not chosen at random. It comes from how pairs of electrons around a central atom repel each other and spread out in three dimensions. In this lesson, you will learn how to count those electron pairs, predict the arrangement they make, and explain why lone...
3.1.3.6 - Bond PolarityBond polarity explains why some covalent bonds have slightly positive and slightly negative ends instead of being perfectly even. The key idea is simple: if two bonded atoms attract the shared pair of electrons by different amounts, the electron distribution becomes uneven. In this lesson, you wi...
3.1.3.7 - Forces Between MoleculesWhen simple molecular substances melt or boil, the covalent bonds inside each molecule are not broken. What changes is the strength of the attractions between neighboring molecules. In this lesson, you will learn how to identify the three intermolecular forces in the specification, explain how th...
1.4 Energetics
3.1.4.1 - Enthalpy ChangeChemical reactions do not just rearrange atoms; they also transfer energy between the reacting system and its surroundings. In this lesson, you will pin down what ΔH means, how to tell whether a reaction is exothermic or endothermic, and how to define the standard enthalpy of combustion and stand...
3.1.4.2 - CalorimetryCalorimetry lets you estimate an enthalpy change from something you can measure directly: a temperature change in a substance of known mass. The heart of the topic is learning what q = mcΔT is really telling you, then linking that energy change to the amount of reaction that took place. Once that...
RP02 - Measurement of an Enthalpy ChangeCalorimetry is how chemists estimate an enthalpy change from a temperature change. In this required practical, you need to turn measurements of mass, volume, and temperature into a value for ΔH in kJ mol^-1, then judge how trustworthy that value is. The same core ideas apply whether you are disso...
3.1.4.3 - Applications of Hess's LawSome enthalpy changes are straightforward to measure directly, but many useful reactions are not. Hess's law lets us calculate the enthalpy change for a difficult reaction by linking it to reactions whose enthalpy changes are known. In this lesson you will learn how to use Hess's law with enthalp...
3.1.4.4 - Bond EnthalpiesWhen a reaction happens, some bonds must be broken and new bonds must form. Bond enthalpies let us estimate the overall enthalpy change by comparing the energy taken in for bond breaking with the energy released by bond formation. In this lesson, you will pin down the exact meaning of mean bond e...
1.5 Kinetics
3.1.5.1 - Collision TheoryCollision theory explains reaction rate by focusing on what happens when particles meet. A reaction does not happen just because particles are present near each other: they must actually collide, and that collision has to be good enough to start chemical change. In this lesson, we will pin down w...
3.1.5.2 - Maxwell-Boltzmann DistributionIn a gas, particles do not all move with the same speed, so they do not all have the same kinetic energy. A Maxwell-Boltzmann distribution shows how those energies are spread across a sample. In this lesson, you will learn how to sketch the curve correctly and how changing temperature changes wha...
3.1.5.3 - Effect of Temperature on Reaction RateTemperature is one of the quickest ways to change how fast a chemical reaction happens. The interesting part is that a small rise in temperature can make a reaction speed up far more than you might expect. That happens because temperature does much more than simply make particles move faster.
RP03 - Investigation of How the Rate of a Reaction Changes with TemperatureIn this required practical, you do not track concentration continuously with an instrument. Instead, you time how long it takes for a fixed amount of sulfur to form as sodium thiosulfate reacts with hydrochloric acid. By keeping everything except temperature the same, you can use that time to com...
3.1.5.4 - Effect of Concentration and PressureThis lesson is about one simple but powerful idea: reactions go faster when reacting particles collide more often. We will follow that idea in two different settings, changing concentration and changing gas pressure. The key is to connect what changes in the container to what happens to collision...
3.1.5.5 - CatalystsCatalysts matter because they let reactions happen faster without needing harsher conditions. In this lesson, you will pin down what a catalyst actually does, see how it changes the energy pathway of a reaction, and use a Maxwell-Boltzmann distribution to explain why a gas reaction becomes faster...
1.6: Chemical equilibria, Le Chatelier's principle and Kc
1.6 Chemical equilibria, Le Chatelier's principle and Kc
1.7 Oxidation, reduction and redox equations
1.8 Thermodynamics
1.9: Rate equations
1.9 Rate equations
1.10: Equilibrium constant Kp
1.10 Equilibrium constant Kp for homogeneous systems
1.11: Electrode potentials and electrochemical cells
1.11 Electrode potentials and electrochemical cells
1.12: Acids and bases
1.12 Acids and bases
Topic 2: Inorganic chemistry
2.1 Periodicity
2.2 Group 2, the alkaline earth metals
2.3: Group 7(17), the halogens
2.3 Group 7(17), the halogens
2.4 Properties of Period 3 elements and their oxides
2.5: Transition metals
2.5 Transition metals
2.6: Reactions of ions in aqueous solution
2.6 Reactions of ions in aqueous solution
Topic 3: Organic chemistry
3.1 Introduction to organic chemistry
3.2: Alkanes
3.2 Alkanes
3.3 Halogenoalkanes
3.4 Alkenes
3.5: Alcohols
3.5 Alcohols
3.6: Organic analysis
3.6 Organic analysis
3.7 Optical isomerism
3.8 Aldehydes and ketones
3.9: Carboxylic acids and derivatives
3.9 Carboxylic acids and derivatives
3.10: Aromatic chemistry
3.10 Aromatic chemistry
3.11: Amines
3.11 Amines
3.12 Polymers
3.13 Amino acids, proteins and DNA
3.14 Organic synthesis
3.15: Nuclear magnetic resonance spectroscopy
3.15 Nuclear magnetic resonance spectroscopy
3.16: Chromatography
3.16 Chromatography