Edexcel GCSE Chemistry (1CH0) Past Papers 2026

Written Examination

Duration: 1h 45m

Written Examination

Duration: 1h 45m

Qualitative analysis — ion tests and gas tests

Examiners explicitly state this is a 'significant weak area'. On Paper 2F June 2024: 'Focus on their knowledge and understanding of the separate chemistry content on Paper 2, particularly testing for anions and cations as described in the specification.' Ion test questions score poorly in every session; candidates confuse iron(II) (green precipitate) with iron(III) (red-brown precipitate), use HCl for the chloride test invalidating the result, and describe the test for chlorine gas when asked about chloride ions.

Paper 2F, Paper 2H

Organic chemistry — displayed formulae, addition reactions, and repeat units

Valency errors, retained double bonds in addition products, and incorrect repeat units are the three most common organic errors. Paper 2H June 2023 notes that the functional group of an alkene was 'poorly understood by many candidates'. Foundation candidates struggle with empirical formulae of hydrocarbons and confuse molecular formula with empirical formula.

Paper 2F, Paper 2H

Electrolysis — conductivity of ionic compounds and predicting products

Paper 1F June 2023: 'Questions that ask about the conductivity of ionic compounds are frequently asked in exams and are usually poorly answered. There is a common misconception that in order to conduct electricity that there needs to be a flow of electrons.' Candidates consistently fail to identify that current is carried by IONS, not electrons.

Paper 1F, Paper 1H

Rates of reaction — collision theory with precise language

Across all sessions, examiners deduct marks for 'more collisions' instead of 'more frequent collisions'. At Foundation level, only 0.6% of candidates scored full marks on a rate question requiring three linked points: rate change → reactant consumption → collision frequency. Examiners also flag that 'scientific terminology was often poor'.

Paper 1F, Paper 2F, Paper 2H

Bond energy calculations and reaction profile diagrams

Paper 2H June 2023: 'Candidates found describing what the reaction profile shows about the energy involved in bond breaking and bond making difficult with the vast majority not scoring.' Common errors: stating that bond formation requires energy input (it releases energy), and placing the activation energy arrow in the wrong position on the profile.

Paper 2H

Titration procedure — equipment names, reading burettes, and concordant results

Paper 1F June 2023: 'Rinsing the burette and pipette with the chemicals to be used, filling the jet of the pipette and repeating the titration without indicator were rarely or never seen.' Paper 1H June 2023 notes common errors reading the burette to 0.05 cm³ precision and reading from the top rather than the bottom of the meniscus.

Paper 1F, Paper 1H

Atom economy and percentage yield calculations

Paper 1F June 2023: 'Candidates found this question about calculating atom economy particularly challenging and there were a lot of responses that scored 0 marks.' Many candidates calculated the formula mass of BOTH products AND reactants in the denominator, producing a denominator twice the correct size. Percentage yield questions were better answered, but incorrect rounding was a common mark loss.

Paper 1F, Paper 1H

Separate Chemistry Higher topics — equilibrium, viscosity, homologous series

Paper 1H June 2023: 'The movement of the position of equilibrium is a challenging topic, and some candidates struggled with interpreting in which direction the equilibrium would shift.' Paper 2H June 2023: very few candidates linked viscosity trends to chain length AND intermolecular forces. Paper 2H June 2024: candidates gave a 'worrying number' of incorrect homologous series definitions.

Paper 1H, Paper 2H