Chemistry › Practicals › OCR PAGs

OCR A-level Chemistry A PAGs: all 12

OCR does not number individual practicals. It sorts the practical work for the endorsement into twelve practical activity groups (PAGs), each a set of techniques, and gives one example activity per group, which your school may replace with another.

From the OCR Chemistry A specification, version 3.1 (May 2026).

Each row gives the group’s number, OCR’s name for it and OCR’s example, then the lesson sections that teach methods using those techniques. Where no lesson sets out a group’s method, the row says so.

Number	Practical activity group, in OCR’s words	Where the method is taught
PAG1	Moles determination OCR’s example activity, in short: composition of copper(II) carbonate	Other boards: x from a percentage of water, in the lesson The mole, the Avogadro constant and molar mass, described in the text rather than set out as a method Edexcel core practical 1: the molar volume of a gas, a method set out in the lesson Gases and the ideal gas equation, without a separate guide OCR’s example, the composition of copper(II) carbonate, is not written up. Heating a hydrate to constant mass is described in the first lesson, and the gas syringe method is set out in the second.
PAG2	Acid–base titration OCR’s example activity, in short: hydrogencarbonate against hydrochloric acid	Make up a standard solution and titrate it against an acid, in the lesson Concentration, volumetric solutions and titration calculations Acid–base titration: making and using a standard solution, the full practical guide OCR’s example titrates a hydrogencarbonate. The method here makes a standard solution of sodium carbonate and titrates hydrochloric acid against it, with the same technique.
PAG3	Enthalpy determination OCR’s example activity, in short: enthalpy change of neutralisation	Measure an enthalpy change in solution with a polystyrene cup, in the lesson Measuring an enthalpy change: calorimetry An enthalpy change in solution: zinc and copper(II) sulfate, the full practical guide Hess's law and enthalpy cycles, described in the lesson’s text rather than set out as a method OCR’s example, the enthalpy change of neutralisation, uses the same polystyrene cup and temperature readings; the Hess’s law lesson shows two such measurements combined in a cycle.
PAG4	Qualitative analysis of ions OCR’s example activity, in short: ions in a mixture of Group 2 salts	Identify cations and anions in solution with test-tube reactions, in the lesson Halide ions, the silver nitrate test, concentrated sulfuric acid, and chlorine in water Identifying ions in solution: anions, Group 2 and ammonium, the full practical guide Identify transition metal ions with hydroxide, ammonia and carbonate, in the lesson Reactions of aqua ions with hydroxide, ammonia and carbonate Identifying metal ions in solution: iron, copper and aluminium, the full practical guide Other boards: Cambridge gas and anion tests, in the lesson Group 2 compounds: solubility, uses and the sulfate test, described in the text rather than set out as a method The method in the halide lesson tests for Group 2 and ammonium cations and the common anions; the one in the aqua ions lesson identifies transition metal ions.
PAG5	Synthesis of an organic liquid OCR’s example activity, in short: a haloalkane	Prepare, purify and test an organic solid and an organic liquid, in the lesson Preparing, purifying and testing an organic solid and liquid Organic preparation and purification: aspirin and ethyl ethanoate, the full practical guide Oxidise an alcohol and distil the aldehyde off as it forms, in the lesson Oxidation and elimination of alcohols Distilling propanal from propan-1-ol, the full practical guide Oxidation and elimination of alcohols, described in the lesson’s text rather than set out as a method OCR’s example, a haloalkane, is made from 2-methylpropan-2-ol in the lesson on alcohols, where it is set out as Edexcel’s core practical 6. The organic preparation method makes ethyl ethanoate, and the propanal method distils an aldehyde as it forms.
PAG6	Synthesis of an organic solid OCR’s example activity, in short: aspirin	Prepare, purify and test an organic solid and an organic liquid, in the lesson Preparing, purifying and testing an organic solid and liquid Organic preparation and purification: aspirin and ethyl ethanoate, the full practical guide OCR’s example, aspirin, is the organic solid in this method and in its guide.
PAG7	Qualitative analysis of organic functional groups OCR’s example activity, in short: unknown organic compounds	Tell an alcohol, aldehyde, alkene and carboxylic acid apart by test, in the lesson Test-tube reactions for functional groups, and high-resolution mass spectrometry Functional group tests: alkenes, acids, aldehydes and alcohols, the full practical guide
PAG8	Electrochemical cells OCR’s example activity, in short: concentration and cell potential	Build two half-cells and a salt bridge and measure the EMF, in the lesson Electrode potentials and the standard hydrogen electrode Measuring the EMF of a cell, the full practical guide
PAG9	Rates of reaction – continuous monitoring method OCR’s example activity, in short: half-life of a reaction	Time a reaction at several temperatures and read the effect on rate, in the lesson Measuring the rate of a reaction Rate and temperature: thiosulfate and acid, the full practical guide Find an order by initial rates and by continuous monitoring, in the lesson Finding orders from initial rates, half-lives and graphs Orders of reaction: iodine and propanone, the full practical guide The rate and temperature method times a reaction at several temperatures; the iodine and propanone method follows one run with a colorimeter, and its lesson reads half-lives from a graph.
PAG10	Rates of reaction – initial rates method OCR’s example activity, in short: order and rate constant	Find an order by initial rates and by continuous monitoring, in the lesson Finding orders from initial rates, half-lives and graphs Orders of reaction: iodine and propanone, the full practical guide
PAG11	pH measurement OCR’s example activity, in short: identifying solutions by pH	Follow a titration with a pH meter and plot the curve, in the lesson Titration curves and choosing an indicator Measuring pH curves, the full practical guide
PAG12	Research skills OCR’s example activity, in short: iron tablets breaking down	Other boards: PAGs, core practicals and research skills, in the lesson Apparatus, techniques and safety: the twelve required practicals in outline, described in the text rather than set out as a method Research skills are described in the lesson on apparatus and techniques, not taught as a method. OCR’s example, iron tablets breaking down, is not written up; titrating the iron in a tablet is taught in the lesson on redox titrations.

PAG 1: Moles determination

Its method is taught in The mole, the Avogadro constant and molar mass.

PAG 2: Acid–base titration

Its method is taught in Concentration, volumetric solutions and titration calculations, and worked in full in Acid–base titration: making and using a standard solution.

PAG 3: Enthalpy determination

Its method is taught in Measuring an enthalpy change: calorimetry, and worked in full in An enthalpy change in solution: zinc and copper(II) sulfate.

PAG 4: Qualitative analysis of ions

Its method is taught in Halide ions, the silver nitrate test, concentrated sulfuric acid, and chlorine in water, and worked in full in Identifying ions in solution: anions, Group 2 and ammonium.

PAG 5: Synthesis of an organic liquid

Its method is taught in Preparing, purifying and testing an organic solid and liquid, and worked in full in Organic preparation and purification: aspirin and ethyl ethanoate.

PAG 6: Synthesis of an organic solid

Its method is taught in Preparing, purifying and testing an organic solid and liquid, and worked in full in Organic preparation and purification: aspirin and ethyl ethanoate.

PAG 7: Qualitative analysis of organic functional groups

Its method is taught in Test-tube reactions for functional groups, and high-resolution mass spectrometry, and worked in full in Functional group tests: alkenes, acids, aldehydes and alcohols.

PAG 8: Electrochemical cells

Its method is taught in Electrode potentials and the standard hydrogen electrode, and worked in full in Measuring the EMF of a cell.

PAG 9: Rates of reaction – continuous monitoring method

Its method is taught in Measuring the rate of a reaction, and worked in full in Rate and temperature: thiosulfate and acid.

PAG 10: Rates of reaction – initial rates method

Its method is taught in Finding orders from initial rates, half-lives and graphs, and worked in full in Orders of reaction: iodine and propanone.

PAG 11: pH measurement

Its method is taught in Titration curves and choosing an indicator, and worked in full in Measuring pH curves.

PAG 12: Research skills

Its method is taught in Apparatus, techniques and safety: the twelve required practicals in outline.

The same methods filed by technique, with the calculations and the errors to avoid: A-level Chemistry practicals

Every numbered statement of this specification, matched to the lessons that teach it: OCR route map

Your school picks the activities for each group. OCR’s specification and practical guidance set the rules for that choice and for how the Practical Endorsement is assessed.

List checked against the specification on 31 October 2026.