What's in the OCR A-Level Chemistry Specification? A Complete Topic-by-Topic Guide

The OCR A-Level Chemistry specification is built around six teaching modules that run across two years, covering physical, inorganic and organic chemistry, with practical skills threaded through every topic rather than taught as a standalone unit. Most UK schools follow OCR Chemistry A (H432), a content-led course, while a smaller number teach OCR Chemistry B, known as Salters (H433), which delivers the same core chemistry through real-world contexts. This guide breaks down what's actually in the specification, how it maps onto the three exam papers, what the required practicals involve, and how to revise a subject this large without drowning in content.

OCR Chemistry A vs Chemistry B (Salters): Which One Are You Doing?

Before diving into topics, it's worth checking which specification your school teaches, because the content is organised differently even though the underlying chemistry overlaps heavily.

• Chemistry A (H432) is the far more widely taught version. It presents chemistry topic by topic in a fairly traditional order: foundational ideas first, then physical chemistry, inorganic chemistry and organic chemistry built up module by module.
• Chemistry B, Salters (H433), is a context-led course. Instead of starting from abstract theory, each unit opens with a real-world scenario (for example, an industrial process or an environmental issue) and introduces the chemistry needed to understand it. Many students and teachers describe the Salters route as more demanding in its written and investigative style, particularly at A2 level.

Because H432 is the specification the large majority of students sit, the rest of this guide focuses on it, though the required chemistry content is broadly comparable between the two.

Overview of the Topic Areas in OCR Chemistry A (H432)

OCR organises the specification into six modules. Module 1 isn't a content topic on its own — it covers the development of practical skills, and its ideas (planning, implementing, analysing and evaluating experimental work) are examined throughout the other five modules rather than in isolation. The remaining modules build up the subject roughly as follows:

• Foundations in chemistry — atomic structure, amount of substance (moles), acid-base and redox reactions, and electron configuration. This module acts as the bridge from GCSE science into the depth expected at A-Level.
• Periodic table and quantitative chemistry — periodicity, group chemistry, and the mathematical and practical techniques used to measure amounts, gas volumes and solution concentrations accurately.
• Physical chemistry themes — enthalpy changes and energetics, reaction rates, chemical equilibrium (including Le Chatelier's principle), and how these three ideas combine in industrial contexts such as improving yield while managing energy demand.
• Organic chemistry — spread across two modules, covering hydrocarbons, functional groups, mechanisms, polymers, and the analytical techniques (such as chromatography and spectroscopy) used to identify organic compounds.
• Further physical and inorganic chemistry at A2, including transition elements, more advanced equilibrium and energetics (entropy, electrode potentials), and acid-base equilibria such as pH and buffers.

Because the specification names and exact module numbering can differ slightly between exam boards' published documents and how individual schools sequence teaching, always check your own centre's scheme of work or the current OCR specification document (ocr.org.uk) for the precise module order you're being taught in.

How the Specification Maps to the Exam Papers

Unlike some other exam boards, OCR Chemistry A does not test each module in a separate paper. Instead, all three written papers draw on content from across the whole two-year course, which is exactly why so many students search for "what's actually in the specification" — you can't just revise module by module and expect each exam to stay in its lane. The three papers are:

1. Periodic Table, Elements and Physical Chemistry (H432/01) — focuses on inorganic and physical chemistry topics, but can still bring in relevant organic or practical-skills questions.
2. Synthesis and Analytical Techniques (H432/02) — focuses on organic chemistry, synthesis routes and analytical methods such as spectroscopy and chromatography.
3. Unified Chemistry (H432/03) — a synoptic paper that can draw on any part of the specification, deliberately testing your ability to connect ideas across physical, inorganic and organic chemistry rather than recall isolated facts.

Each paper is worth a significant chunk of the overall A-Level grade, and all three include a mix of short-answer, extended-response and multiple-choice or structured questions, plus questions that test practical and mathematical skills even though the Practical Endorsement itself is reported separately.

Required Practicals and the Practical Endorsement

Practical work in OCR Chemistry A is organised into Practical Activity Groups (PAGs), twelve in total, spread across the two years of the course. PAGs 1 to 5 typically map onto first-year content, PAGs 6 to 9 onto second-year content, PAGs 10 and 11 are less scaffolded investigative activities that draw together skills from across the course, and PAG 12 covers research skills, often on a topic your teacher or you choose.

Two important points students often misunderstand:

• The Practical Endorsement is reported separately as a pass or not classified — it does not contribute marks to your overall A-Level grade, but many universities (particularly for chemistry, biochemistry and related degrees) expect to see a pass, so it's not optional in practice.
• Questions based on practical techniques and data analysis from these practicals do appear in the three written exam papers, worth a meaningful proportion of the overall marks, so treating practicals as "just something to get signed off" is a mistake.

Common practical themes include titrations and volumetric analysis, rates of reaction investigations, calorimetry for enthalpy changes, preparation and purification of organic compounds, and use of instrumental techniques such as chromatography.

A Systematic Way to Revise a Specification This Large

OCR A-Level Chemistry covers a genuinely large volume of content spread across six modules and three synoptic papers, so an unstructured "read the textbook cover to cover" approach tends to fall apart by February of Year 13. A more systematic approach works better:

• Build a full topic checklist first. Break the six modules down into their individual sub-topics before you start revising, so you always know what's left rather than guessing.
• Revise physical, inorganic and organic chemistry in parallel, not sequentially — since Unified Chemistry can combine any of them, leaving organic chemistry until last (a common trap) leaves it under-revised right when the hardest synoptic questions need it.
• Practise past papers by question type, not just by paper. Group together every mechanism question, every calculation question, every practical-based question you can find, and drill each type until the method is automatic.
• Keep a running list of definitions and mechanisms — chemistry examiners are strict on precise wording, and vague answers lose marks even when the underlying understanding is correct.
• Revisit "finished" topics on a rolling basis rather than moving on and never returning, since forgetting curves hit chemistry content (especially organic mechanisms) hard.

This is where a large, synoptic specification like OCR Chemistry A becomes genuinely hard to manage with a notebook and a spreadsheet — you need to actually see, topic by topic, where the gaps are.

How Applaa Helps You Track Progress Across a Large Specification

Applaa is a free UK learning platform built around exactly this problem: A-Level specifications, and OCR Chemistry in particular, are too large and too interconnected to revise effectively without a clear map of what you actually know. Applaa's AI tutor lets you work through GCSE and A-Level topics — including the physical, inorganic and organic chemistry content covered in OCR Chemistry A — while quietly tracking which areas you're confident in and which ones keep tripping you up.

Instead of revising in the dark, Applaa surfaces the topics you're weakest on so you can prioritise revision time where it actually moves your grade, rather than re-reading chapters you've already mastered. For a subject where the final exams are deliberately synoptic and can mix physical, inorganic and organic content in a single question, having a live picture of your progress across all six modules — not just the one you revised last week — makes a real difference.

If you're working through OCR A-Level Chemistry and want a clearer view of your own progress across the specification, try Applaa's free AI tutor to practise topic by topic and see exactly where your revision needs to go next.