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OCR A Level Chemistry A (H432)

Select a specification section to access structured OCR revision notes, practical links and exam practice.

Foundations in Chemistry

AS + A LevelPapers 1, 2 and 3
An atom with its nucleus and electron shells2.1.1Atomic Structure and IsotopesProtons, neutrons and electrons, isotopes and relative masses.Start revisingA level balance with the same atoms in each pan2.1.2Compounds, Formulae and EquationsFormulae of ionic compounds and balanced equations.Start revisingParticles being weighed on a balance2.1.3Amount of SubstanceThe mole, formulae, hydrated salts, percentage yield and atom economy.Start revisingMetal fizzing in acid beside a pile of carbonate powder2.1.4AcidsAcids and alkalis, neutralisation, standard solutions and titration calculations.Start revisingElectrons moving from one particle to another2.1.5RedoxOxidation numbers, electron transfer and redox reactions.Start revisingAn electron pulled clear of an atom2.2.1Electron StructureShells, sub-shells and orbitals, and how electrons fill them.Start revisingAn ionic lattice beside a covalent molecule2.2.2Bonding and StructureIonic and covalent bonding, shapes of molecules, polarity and intermolecular forces.Start revising

Periodic Table and Energy

AS + A LevelPapers 1 and 3
The outline of the periodic table3.1.1PeriodicityThe Periodic Table, ionisation energies and the trends in melting points.Start revisingA metal ribbon burning in tongs3.1.2Group 2Trends down the group, redox reactions and the uses of Group 2 compounds.Start revisingThree jars of halogens: gas, liquid and solid3.1.3The HalogensTrends in the halogens, disproportionation of chlorine and tests for halide ions.Start revisingA white precipitate beside gas bubbling through limewater3.1.4Qualitative AnalysisTest-tube tests for carbonate, sulfate, halide and ammonium ions.Start revisingAn energy profile for a reaction giving out heat3.2.1Enthalpy ChangesEnthalpy changes, calorimetry, Hess's law and average bond enthalpies.Start revisingTwo particles colliding, with a stopclock3.2.2Reaction RatesCollision theory, catalysts and the Boltzmann distribution.Start revisingA level balance with forward and reverse arrows3.2.3Chemical EquilibriumDynamic equilibrium, shifting the position of equilibrium and Kc.Start revising

Core Organic Chemistry

AS + A LevelPapers 2 and 3
A carbon chain with a functional group4.1.1Basic Concepts of Organic ChemistryNaming, formulae, functional groups, isomerism and curly arrows.Start revisingA tetrahedral alkane molecule and a gas flame4.1.2AlkanesBonding and boiling points, combustion and radical substitution.Start revisingA carbon to carbon double bond4.1.3AlkenesElectrophilic addition, addition polymers and dealing with polymer waste.Start revisingAn alcohol molecule with its OH group picked out4.2.1AlcoholsProperties of alcohols, oxidation, esterification, elimination and substitution.Start revisingA nucleophile approaching a halogenoalkane4.2.2HaloalkanesNucleophilic substitution, rates of hydrolysis, and CFCs and the ozone layer.Start revisingA distillation set with a side condenser and receiver4.2.3Organic SynthesisQuickfit apparatus, reflux and distillation, and two-stage synthetic routes.Start revisingA spectrum on a monitor4.2.4Analytical TechniquesInfrared spectroscopy and mass spectrometry to identify organic compounds.Start revising

Physical Chemistry and Transition Elements

A Level onlyPapers 1 and 3
A concentration graph with a tangent drawn on it5.1.1How Fast?Orders, rate equations, half-life, the rate-determining step and the Arrhenius equation.Start revisingA gas mixture in a cylinder with a pressure gauge5.1.2How Far?Kc and Kp calculations, and how conditions affect the constants.Start revisingA coloured acid to alkali scale and a flask5.1.3Acids, Bases and BuffersBrønsted-Lowry acids, pH, Ka, Kw, buffers and neutralisation curves.Start revisingA cube lattice of alternating large and small ions5.2.1Lattice EnthalpyLattice enthalpy, Born-Haber cycles, and enthalpies of solution and hydration.Start revisingOrdered particles spreading into disorder5.2.2Enthalpy and EntropyEntropy, free energy change and the feasibility of reactions.Start revisingA metal strip in its ion solution exchanging electrons and ions5.2.3Redox and Electrode PotentialsRedox titrations, electrode potentials, storage cells and fuel cells.Start revisingAn octahedral complex with coloured solutions5.3.1Transition ElementsComplex ions, stereoisomerism, ligand substitution, redox and catalysis.Start revisingTest tubes of coloured precipitates5.3.2Qualitative AnalysisTests for anions, ammonium and transition element cations.Start revising

Organic Chemistry and Analysis

A Level onlyPapers 2 and 3
A benzene ring with delocalised electrons6.1.1Aromatic CompoundsThe structure of benzene, electrophilic substitution, phenols and directing groups.Start revisingA carbonyl molecule and a silver mirror test6.1.2Carbonyl CompoundsOxidation, reduction, nucleophilic addition and tests for aldehydes and ketones.Start revisingTwo carboxylic acid molecules paired by hydrogen bonds6.1.3Carboxylic Acids and EstersCarboxylic acids, esters and acyl chlorides, and their reactions.Start revisingAn amine molecule with its lone pair6.2.1AminesHow amines are prepared and how they behave as bases.Start revisingA protein chain folding into a helix6.2.2Amino Acids, Amides and ChiralityAmino acids, amides, optical isomers and chirality.Start revisingMonomers joining into a polymer chain6.2.3Polyesters and PolyamidesCondensation polymers and the hydrolysis of polyesters and polyamides.Start revisingAn open chain, a ring and an aromatic ring of carbon atoms6.2.4Carbon–Carbon Bond FormationExtending the carbon chain with nitriles and Friedel-Crafts reactions.Start revisingA multi-step synthesis route6.2.5Organic SynthesisPractical skills, functional group tests and planning a synthesis.Start revisingA gas chromatograph oven with a coiled column and peaks6.3.1Chromatography and Qualitative AnalysisThin-layer and gas chromatography, and tests for functional groups.Start revisingA magnet with a sample tube and NMR peaks6.3.2SpectroscopyCarbon-13 and proton NMR, and combining the evidence from several spectra.Start revising

Practical Activity Groups

Module 1 skillsAssessed in all three papers
All practicals
Collecting a gas over waterPAG 1Molar Volume of a GasMeasure the volume of gas made and find its molar volume.Start revisingA polystyrene cup calorimeter with a thermometerPAG 3Enthalpy Change via Hess's LawFind an enthalpy change you cannot measure directly, using Hess's law.Start revisingA burette over a conical flaskPAG 2Concentration of HCl by TitrationRun an accurate acid and alkali titration and work out the concentration.Start revisingA volumetric flask and wash bottlePAG 2Preparation of a Standard SolutionMake up a solution of exact concentration in a volumetric flask.Start revisingThree test tubes in a water bath clouding at different speedsHydrolysis ratesHydrolysis of HalogenoalkanesCompare how fast different haloalkanes hydrolyse.Start revisingA separating funnel with two layersPAG 5Chlorination of 2-methylpropan-2-olMake a tertiary haloalkane, then separate and purify it.Start revisingA flask heated under refluxPAG 5Oxidation of an AlcoholOxidise an alcohol to an aldehyde by distillation and to an acid under reflux.Start revisingA flame test and a test tube precipitatePAG 4 and 7Analysis of Inorganic and Organic UnknownsUse test-tube reactions to identify unknown ions and functional groups.Start revisingA reaction flask on a top-pan balance losing massRatesRates of ReactionFollow the rate of a reaction by timing an observation or collecting gas.Start revisingA crucible heated on a tripod beside a balancePAG 1Gravimetric and Composition AnalysisFind amounts and formulae by mass, including water of crystallisation.Start revisingA reaction flask with a gas syringe and stopclockPAG 9 and 10Following Reaction RatesFind orders of reaction by continuous monitoring and initial rates.Start revisingA reaction timed in a hot water bathActivation energyFinding the Activation EnergyTime a reaction at several temperatures and plot the Arrhenius graph.Start revisingA pH probe in a stirred beakerPAG 11The Ka of a Weak AcidUse a pH meter to find Ka for a weak acid.Start revisingAn electrochemical cell with a voltmeterPAG 8Electrochemical CellsBuild cells, measure their voltage and compare electrode potentials.Start revisingA redox titration with a purple solution in the buretteRedox titrationsRedox TitrationsManganate(VII) and iodine-thiosulfate titrations to find unknown amounts.Start revisingDeep blue crystals on a watch glass beside a flask in iceComplex prepPreparing a ComplexPrepare a coloured complex and isolate the crystals.Start revisingA white spotting tile with drops of coloured solutionsUnknowns (A Level)Analysis of Unknowns (A Level)Identify transition element ions and organic unknowns from test-tube reactions.Start revisingCrystals filtered in a Buchner funnelPAG 6Preparation of AspirinMake aspirin, purify it by recrystallisation and check its melting point.Start revisingA thin-layer chromatography plate in a beakerTLCThin-Layer ChromatographySeparate compounds on a TLC plate and compare their Rf values.Start revisingPAG 12Research SkillsStart revising
Introduction

OCR
A Level
Chemistry

OCR A Level Chemistry A (H432) is a linear qualification assessed at the end of the two-year course. The content is organised into six modules: practical skills, foundations in chemistry, the periodic table and energy, core organic chemistry, physical chemistry and transition elements, and organic chemistry and analysis. Modules 1 to 4 also form the AS Level (H032).

A Linear Qualification

OCR A Level Chemistry A is assessed through three written papers taken at the end of the course. It is structured around specification code H432 and uses the A*-E A Level grading scale.

Practical Endorsement

Students complete a minimum of 12 practical activity groups (PAGs) and develop practical competencies throughout the course. Module 1 practical skills are assessed in the written papers, while the Practical Endorsement in Chemistry (H432/04) is reported separately as a pass.

AS Level Chemistry

OCR AS Level Chemistry A (H032) is a separate standalone qualification. The AS content is Modules 1 to 4 of the A Level and is assessed by two written papers.

The Three Papers – How The A Level Is Assessed

The OCR A Level is assessed through three externally examined papers. Papers 1 and 2 divide the content by module, while Paper 3 draws across all six modules and places a strong emphasis on synoptic reasoning and practical skills.

Paper 1 – Periodic Table, Elements, Physical and Inorganic Chemistry

Paper code: H432/01
Written examination: 2 hours 15 minutes | 100 marks | 37% of total A Level

Assesses content from Modules 1, 2, 3 and 5. This includes atomic structure, amount of substance, acids, redox, bonding and structure, periodicity, Group 2, the halogens, enthalpy, rates, equilibrium, lattice enthalpy, entropy, electrode potentials and transition elements.

Paper 2 – Synthesis and Analytical Techniques

Paper code: H432/02
Written examination: 2 hours 15 minutes | 100 marks | 37% of total A Level

Assesses content from Modules 1, 2, 4 and 6. This includes basic organic concepts, alkanes, alkenes, alcohols, haloalkanes, organic synthesis, analytical techniques, aromatic compounds, carbonyls, carboxylic acids, amines, amino acids, polymers, and NMR spectroscopy and chromatography.

Paper 3 – Unified Chemistry

Paper code: H432/03
Written examination: 1 hour 30 minutes | 70 marks | 26% of total A Level

Assesses content from all six modules. This paper draws the course together with synoptic questions, extended response and practical-based questions across physical, inorganic and organic chemistry.

OCR Specification Pathway

OCR Chemistry A is organised into modules and numbered sections rather than Edexcel-style numbered topics.

Modules 2 and 3 – Foundations, Periodic Table and EnergyAtomic structure, amount of substance, acids, redox, electron structure, bonding, periodicity, Group 2, the halogens, enthalpy changes, reaction rates and equilibrium.
Modules 4 and 6 – Organic Chemistry and AnalysisBasic concepts, alkanes, alkenes, alcohols, haloalkanes, synthesis, analytical techniques, aromatic compounds, carbonyls, acids, amines, polymers, chromatography and spectroscopy.
Module 5 – Physical Chemistry and Transition ElementsRates, equilibrium, acids, bases and buffers, lattice enthalpy, entropy, redox and electrode potentials, transition elements and qualitative analysis.
Full Qualification

Take the A Level if…

OCR A Level Chemistry A – H432

You need chemistry for university entry, particularly for medicine, dentistry, pharmacy, biochemistry, chemical engineering or related science degrees. The full A Level is the standard two-year qualification used for UK university admissions.

Standalone Award

Take the AS Level if…

OCR AS Level Chemistry A – H032

You want a recognised one-year chemistry qualification without committing to the full A Level. The AS is a standalone qualification and does not contribute to the final A Level grade.

Watch a Chemistry Lesson Preview

See how OLS uses visual explanation, molecular models and specialist teacher commentary to support difficult A Level Chemistry topics.

Official Specification

The official OCR A Level Chemistry A specification covering the six modules, assessment structure, mathematical requirements and the practical endorsement.

OCR Chemistry A Specification →

OCR Exam Materials

OCR’s official exam materials for A Level Chemistry A, including exam papers, mark schemes and examiner reports.

OCR Exam Materials →

Chemistry Reference Library

LibreTexts Chemistry is a free, open-access chemistry library covering a wide range of topics at A Level and beyond, useful for deeper reading and alternative explanations of difficult concepts.

LibreTexts Chemistry →

FAQ

The specification is organised into six modules, each divided into numbered sections such as 2.1.3 Amount of substance or 4.1.3 Alkenes, with lettered learning outcomes inside each section. OLS uses these OCR section references directly so students can revise by exact learning outcome.
There are three written papers: Paper 1, Paper 2 and Paper 3. Papers 1 and 2 are each worth 37% of the A Level, while Paper 3 is worth 26%.
No. OCR uses module and section references such as 2.1.1 Atomic structure and isotopes, 3.2.1 Enthalpy changes and 4.1.3 Alkenes, with learning outcomes labelled (a), (b), (c) and so on.
Yes. Module 1 practical skills are assessed across all three written papers. Students also complete practical activity groups (PAGs) during the course for the separately reported Practical Endorsement.
No. OCR AS Level Chemistry A (H032) is a standalone qualification. It covers Modules 1 to 4 but does not contribute to the final A Level grade.
OCR Chemistry A includes substantial mathematical work: at least 20% of the marks assess mathematics at Level 2 or above, covering moles, concentrations, energetics, equilibria, rates, logarithms, graph work and practical-data analysis. Students should be confident rearranging equations and interpreting quantitative data.