Pearson Edexcel · International A-Level

Recent past papers

77 paper and mark-scheme pairs

Handouts, exercise sheets and slides

Shared topic documents retain their source course and topic titles. Use your chosen board’s specification for coverage, tier and exam requirements.

Handouts · A-Level Chemistry (37)

Exercise sheets · A-Level Chemistry (90)

Presentation slides · A-Level Chemistry (37)

Course units and learning goals

These lessons teach selected course objectives. Check the remaining coverage gaps; the material is not a complete preparation programme.

Lessons →Vocabulary practice →

1 · Structure, Bonding and Introduction to Organic Chemistry

The SI unit of amount of substance.
Calculate the amount available for each reactant and divide by its coefficient. The smaller ratio limits the reaction. Use that reactant to calculate the maximum product before comparing actual yield.
Write the balanced equation first, include units in molar masses, then convert each given mass or solution volume into amount. Convert cubic centimetres to cubic decimetres before using concentration in moles per cubic decimetre.
Attraction between oppositely charged ions.
To explain a bulk property, name the structure, particles, forces and mobile charge carriers. Simple molecular substances can have strong covalent bonds inside molecules but weak attractions between molecules.
Compare substances using evidence such as melting point, conductivity when solid and molten, and solubility. One property rarely proves a structure; use a pattern of evidence.
An atom group determining characteristic reactions.
Distinguish addition, substitution, oxidation and polymerization by tracing bonds before and after reaction. Conditions and reagents belong to the reaction arrow; they are not interchangeable labels.
Draw displayed or structural formulae with the correct number of bonds at each carbon. Use a carbon count to check a proposed synthesis. At advanced level, track reagents and conditions through multistep routes.

mole: The SI unit of amount of substance
limiting reagent: The reactant that limits the possible product amount
ionic bond: Attraction between oppositely charged ions
delocalized electron: An electron not confined to one atom or bond
functional group: An atom group determining characteristic reactions
isomer: A compound sharing a formula but differing in structure

2 · Energetics, Group Chemistry, Halogenoalkanes and Alcohols

Transferring energy to the surroundings.
Use energy transferred = mass × specific heat capacity × temperature change. Convert joules to kilojoules before dividing by reaction amount. An exothermic molar enthalpy change has a negative sign.
Use insulation and a lid, measure starting temperatures consistently, stir, and record a temperature-time series. Estimate the reaction temperature from an appropriate extrapolation rather than ignoring cooling during measurement.
Loss of electrons.
Predict products using the specified electrolyte and electrode material. In an aqueous solution, hydrogen or oxygen may form because water-related species compete. Molten salts contain only the ions of the salt.
Use a low-voltage direct-current supply, approved electrodes, and the school risk assessment. Collect gases only by an approved method. Keep chlorine demonstrations teacher-controlled; do not ask students to generate hazardous gases independently.
The energy barrier for a reaction pathway.
A product-time graph has a steeper gradient where rate is larger. A tangent estimates instantaneous rate; a secant gives average rate over an interval. The final plateau reflects the total collected product under the stated conditions.
For gas production, check apparatus for leaks, start timing consistently and record volume at regular intervals. Keep concentration, reactant amount and surface area controlled when changing temperature.
An atom group determining characteristic reactions.
Distinguish addition, substitution, oxidation and polymerization by tracing bonds before and after reaction. Conditions and reagents belong to the reaction arrow; they are not interchangeable labels.
Draw displayed or structural formulae with the correct number of bonds at each carbon. Use a carbon count to check a proposed synthesis. At advanced level, track reagents and conditions through multistep routes.

exothermic: Transferring energy to the surroundings
enthalpy change: Heat change at constant pressure for a stated process
oxidation: Loss of electrons
reduction: Gain of electrons
activation energy: The energy barrier for a reaction pathway
rate: Change in a measured quantity per unit time
functional group: An atom group determining characteristic reactions
isomer: A compound sharing a formula but differing in structure

3 · Practical Skills in Chemistry I

The volume delivered between two burette readings.
Calculate the known amount first, apply the stoichiometric ratio, then divide by the unknown solution volume in cubic decimetres. Use concordant titres as required by the school method and report the accepted values.
Rinse the burette with its solution and the pipette with the solution it transfers. Rinse the flask with distilled water. Add titrant slowly near the endpoint, swirl, and read the meniscus at eye level. Use a white tile and appropriate eye protection.
Separation using two phases.
Rf is distance travelled by a component divided by distance travelled by the solvent front, both measured from the baseline. Compare under the same conditions; an Rf value alone does not establish identity across different solvents.
Use pencil for the baseline, keep spots above solvent level, mark the solvent front promptly, and run known references alongside unknowns. For ion tests, use clean equipment and separate aliquots to avoid carrying reagents into later tests.
A quantified limitation on a measured result.
For a product or quotient, adding fractional uncertainties is a common maximum-uncertainty approximation. For a difference, add absolute uncertainties. A nonzero intercept can reveal an offset or an incomplete model.
Show units on axes and choose a sensible scale. Plot uncertainty bars where justified, draw a best-fit line rather than joining every point, and estimate steepest and shallowest plausible gradients when the course method calls for them.

titre: The volume delivered between two burette readings
equivalence point: The point of stoichiometric reaction completion
chromatography: Separation using two phases
Rf: Spot distance divided by solvent-front distance
uncertainty: A quantified limitation on a measured result
systematic error: A consistent measurement bias

4 · Rates, Equilibria and Further Organic Chemistry

The energy barrier for a reaction pathway.
A product-time graph has a steeper gradient where rate is larger. A tangent estimates instantaneous rate; a secant gives average rate over an interval. The final plateau reflects the total collected product under the stated conditions.
For gas production, check apparatus for leaks, start timing consistently and record volume at regular intervals. Keep concentration, reactant amount and surface area controlled when changing temperature.
A state with equal forward and reverse reaction rates.
A concentration or pressure change disturbs the balance. The system responds toward a new equilibrium. Temperature changes can also change the equilibrium constant; a catalyst changes how quickly equilibrium is reached.
State the balanced equation and whether the forward reaction is exothermic before predicting a temperature effect. Count gas coefficients when considering pressure; pressure has no composition effect when gaseous amounts are equal on both sides.
Transferring energy to the surroundings.
Use energy transferred = mass × specific heat capacity × temperature change. Convert joules to kilojoules before dividing by reaction amount. An exothermic molar enthalpy change has a negative sign.
Use insulation and a lid, measure starting temperatures consistently, stir, and record a temperature-time series. Estimate the reaction temperature from an appropriate extrapolation rather than ignoring cooling during measurement.
An atom group determining characteristic reactions.
Distinguish addition, substitution, oxidation and polymerization by tracing bonds before and after reaction. Conditions and reagents belong to the reaction arrow; they are not interchangeable labels.
Draw displayed or structural formulae with the correct number of bonds at each carbon. Use a carbon count to check a proposed synthesis. At advanced level, track reagents and conditions through multistep routes.

activation energy: The energy barrier for a reaction pathway
rate: Change in a measured quantity per unit time
equilibrium: A state with equal forward and reverse reaction rates
reversible reaction: A reaction that can proceed in both directions
exothermic: Transferring energy to the surroundings
enthalpy change: Heat change at constant pressure for a stated process
functional group: An atom group determining characteristic reactions
isomer: A compound sharing a formula but differing in structure

5 · Transition Metals and Organic Nitrogen Chemistry

Loss of electrons.
Predict products using the specified electrolyte and electrode material. In an aqueous solution, hydrogen or oxygen may form because water-related species compete. Molten salts contain only the ions of the salt.
Use a low-voltage direct-current supply, approved electrodes, and the school risk assessment. Collect gases only by an approved method. Keep chlorine demonstrations teacher-controlled; do not ask students to generate hazardous gases independently.
An atom group determining characteristic reactions.
Distinguish addition, substitution, oxidation and polymerization by tracing bonds before and after reaction. Conditions and reagents belong to the reaction arrow; they are not interchangeable labels.
Draw displayed or structural formulae with the correct number of bonds at each carbon. Use a carbon count to check a proposed synthesis. At advanced level, track reagents and conditions through multistep routes.
Separation using two phases.
Rf is distance travelled by a component divided by distance travelled by the solvent front, both measured from the baseline. Compare under the same conditions; an Rf value alone does not establish identity across different solvents.
Use pencil for the baseline, keep spots above solvent level, mark the solvent front promptly, and run known references alongside unknowns. For ion tests, use clean equipment and separate aliquots to avoid carrying reagents into later tests.

oxidation: Loss of electrons
reduction: Gain of electrons
functional group: An atom group determining characteristic reactions
isomer: A compound sharing a formula but differing in structure
chromatography: Separation using two phases
Rf: Spot distance divided by solvent-front distance

6 · Practical Skills in Chemistry II

The volume delivered between two burette readings.
Calculate the known amount first, apply the stoichiometric ratio, then divide by the unknown solution volume in cubic decimetres. Use concordant titres as required by the school method and report the accepted values.
Rinse the burette with its solution and the pipette with the solution it transfers. Rinse the flask with distilled water. Add titrant slowly near the endpoint, swirl, and read the meniscus at eye level. Use a white tile and appropriate eye protection.
A quantified limitation on a measured result.
For a product or quotient, adding fractional uncertainties is a common maximum-uncertainty approximation. For a difference, add absolute uncertainties. A nonzero intercept can reveal an offset or an incomplete model.
Show units on axes and choose a sensible scale. Plot uncertainty bars where justified, draw a best-fit line rather than joining every point, and estimate steepest and shallowest plausible gradients when the course method calls for them.

titre: The volume delivered between two burette readings
equivalence point: The point of stoichiometric reaction completion
uncertainty: A quantified limitation on a measured result
systematic error: A consistent measurement bias

Preparing for this qualification

Six separately assessed units; IAS uses Units 1–3, IAL uses Units 1–6.
Units 3 and 6 are written practical-skills examinations based on experimental experience; they are not a Cambridge hands-on practical paper.
Retain core-practical numbering from the acquired specification. Unit weights, marks and times are in the assessment evidence manifest.

Teaching coverage still needed

Full topic 1–5 statement coverage remains.
Intermolecular forces, Groups 1/2/7, halogenoalkanes and alcohol chemistry remain.
All AS core practicals, preparation methods and practical-paper objectives remain.
Rate equations, entropy, acid-base equilibria, carbonyls/acids/chirality remain.
Transition-metal complexes, electrode potentials, organic nitrogen, synthesis and spectroscopy remain.
A2 synthesis, purification, quantitative analysis and practical-paper coverage remain.