Explore
GCSEAQA
Chemistry
Start learning
Browse allCurriculum Modules
What an element is, and why elements are listed in the periodic tableHow compounds form from elementsMixtures, pure substances, and why separation worksConservation of mass in chemical reactionsWhy chemical equations must be balancedWriting state symbols: (s), (l), (g), (aq)Using scientific vocabulary precisely in exam answersUsing units correctly in chemistry calculationsSignificant figures and standard form in chemistry contextsIdentifying independent, dependent, and control variablesWriting a testable hypothesisAccuracy, precision, and repeatability in measurementsReducing uncertainty: repeats, ranges, and anomaliesRisk assessment: hazards, risks, and control measuresInterpreting graphs and spotting proportionality
Elements, compounds, and mixtures: spotting the differenceSimple model of the atom: nucleus and electronsProtons, neutrons, and electrons: charges and relative massesAtomic number and mass numberWorking out numbers of subatomic particles from isotope notationIsotopes: what changes and what stays the sameRelative atomic mass: why it’s not a whole numberElectron shells and electron arrangement for the first 20 elementsWhy atoms form ions: gaining and losing electronsDevelopment of the atom: changing models with evidencePeriodic table layout: periods and groupsMetals vs non-metals: key physical propertiesGroup 0: why noble gases are unreactiveGroup 1: reactions with water and trends down the groupGroup 7: halogens, displacement, and trends down the groupTransition metals: key differences from Group 1 (including catalysts)What a “displacement reaction” means in terms of reactivity
Chemical bonds as electrostatic attractionsIonic bonding: metal + non-metal electron transferDrawing dot-and-cross diagrams for ions and ionic compoundsIonic lattices and why ionic compounds have high melting pointsWhy ionic compounds conduct when molten/in solution but not solidCovalent bonding: sharing electronsDot-and-cross diagrams for simple covalent moleculesComparing simple molecular substances and giant structuresMetallic bonding: positive ions and delocalised electronsExplaining conductivity and malleability in metalsGiant covalent structures: diamond and graphiteGraphene: structure and propertiesSilicon dioxide as a giant covalent structurePolymers: long chains and low melting pointsIntermolecular forces and boiling point trends (Higher)States of matter: particle model and energy changesInternal energy and what changes during heating/cooling (Higher)Density: how to calculate and interpretChanges of state and what a heating curve showsNanoparticles: what “nano” means and why properties changeUses and risks of nanoparticles
Relative formula mass: calculating from the periodic tableThe mole as “amount of substance”Converting between mass, moles, and MrBalancing equations to calculate reacting massesLimiting reactants (Higher)Conserving atoms when predicting productsTheoretical yield: meaning and calculation (Higher)Percentage yield: calculation and why it’s less than 100%Atom economy: calculation and linking to sustainabilityConcentration in g/dm³ and converting unitsConcentration in mol/dm³ (Higher)Using concentration to calculate moles in solutionGas volumes and moles at room temperature (Higher)Titration calculations: building a clear method (Higher)Using ratios in balanced equations confidently
Acids, alkalis, and the pH scaleIndicators: colour changes and what they showNeutralisation: making salts and waterNaming salts from the acid usedReactions of acids with metals: salt + hydrogenReactions of acids with carbonates: salt + water + carbon dioxideMaking a soluble salt from an insoluble base (method + reasoning)Crystallisation: producing a pure dry sampleStrong vs weak acids: what “weak” means (Higher)Electrolytes and why ions are needed for conductionElectrolysis of molten ionic compoundsElectrolysis of aqueous solutions: competing ions (Higher)Half equations for electrolysis at each electrode (Higher)Metal extraction basics: reduction and oxidationOxidation and reduction using electron transfer (Higher)Redox in terms of oxygen loss/gain (foundation-friendly)
Exothermic vs endothermic reactions: energy transfer ideaReaction profiles: what axes and shapes meanActivation energy on a reaction profileBond breaking vs bond making: where energy goesCalculating energy change using bond energies (Higher)Temperature changes and how to measure them safelyNeutralisation temperature change: what affects the resultFuels and energy transfer in combustionComparing fuels using energy per mass (Higher)Evaluating errors in temperature-change practicals
What “rate of reaction” means in practical termsMeasuring rate by gas volume, mass loss, or colour changeCalculating mean rate from dataDrawing and interpreting rate graphsTangents and instantaneous rate (Higher)Collision theory: why particles must collideActivation energy in collision theory termsTemperature and rate: frequency and energy of collisionsConcentration/pressure and rate: collision frequencySurface area and rate: surface area to volume ratioCatalysts and how they work (lower activation energy)Enzymes as biological catalystsReversible reactions and the reversible reaction symbolDynamic equilibrium: forward rate equals reverse rateShifting equilibrium by concentration (Higher)Shifting equilibrium by temperature (Higher)Shifting equilibrium by pressure (Higher)Le Chatelier’s principle for predictions (Higher)Choosing conditions for yield, rate, cost, and safety (Haber-style)
Crude oil as a finite resource and why we process itHydrocarbons and what “saturated” meansAlkanes: general formula and bondingFractional distillation: separating crude oil by boiling pointProperties of fractions: patterns with chain lengthCracking: why we do it and what we makeAlkenes: double bonds and general formulaTesting for alkenes using bromine waterAddition reactions of alkenes (concept + examples)Addition polymerisation: making polymers from alkenesComparing properties of small alkenes vs polymersEthanol production by fermentation: conditions and equationEthanol production by hydration of ethene (Higher)Comparing fermentation vs hydration (yield, rate, purity)Carboxylic acids: acids in organic chemistry (Higher)Esters: making esters and recognising the smell (Higher)Condensation polymerisation basics (Higher)
Pure substances and why melting/boiling points matterChromatography basics: stationary vs mobile phaseInterpreting chromatograms: spots, colours, and separationCalculating Rf values (Higher)Flame tests for common metal ionsPrecipitation tests for halide ions (chloride, bromide, iodide)Sulfate test and the precipitate colourCarbon dioxide test using limewaterHydrogen test using a lit splintOxygen test using a glowing splintChlorine test using damp litmus paperInstrumental analysis: speed, accuracy, sensitivityGas chromatography basics (Higher)Mass spectrometry basics (Higher)Identifying elements from spectra (Higher)Making a reasoned identification from multiple tests
Proportions of gases in the atmosphereHow Earth’s early atmosphere formed (volcanoes, oceans, oxygen rise)The greenhouse effect: what it is and why it happensHuman causes of climate change: greenhouse gasesEffects of climate change: environmental and societal impactsCarbon footprint and reducing emissionsAtmospheric pollutants: CO, SO₂, NOₓ, particulatesAcid rain: formation and effectsControlling sulfur dioxide emissions from fuelsPhotochemical smog: formation and impact (Higher)Corrosion and rusting: oxygen and water neededPreventing rust: barrier methods, galvanising, sacrificial protectionWater as a resource: potable water and why it mattersTreating water: filtration, sterilisation, and distillationDesalination: benefits and energy costs (Higher)
Using finite resources sustainablyLife cycle assessments: what’s included and what’s missedReducing, reusing, and recycling: where each fits bestExtracting metals: mining vs recycling (energy and pollution)Corrosion as a waste of resources and how prevention helpsAlloys: why mixing metals changes propertiesCeramics: properties, uses, and limitationsPolymers: thermosoftening vs thermosetting (Higher)Composites: why combining materials improves performanceHaber process: making ammonia and why it mattersConditions in Haber process: equilibrium vs rate vs costNPK fertilisers and why plants need nitrates/phosphates/potassiumProducing fertilisers: making ammonia as a starting pointUsing fertilisers responsibly: eutrophication and environmental issues
Making a soluble salt and producing crystals (chemistry-only)Titration: finding the reacting volumes accurately (chemistry-only)Electrolysis: products at electrodes and half equationsTemperature change: comparing exothermic and endothermic reactionsRates of reaction: investigating concentration effects (gas/colour methods)Chromatography: separating dyes and calculating Rf valuesIdentifying ions: using flame tests and precipitation testsWater purification: analysing and producing potable water (AQA)
