Calculations account for a significant number of marks across A-Level Chemistry, yet they're one of the areas where students most commonly lose marks through avoidable mistakes. Calculations account for up to 30% of the entire curriculum

This guide focuses on five of the most frequently examined calculation-heavy topics and teaches the exact method examiners expect to see. Rather than simply providing answers, it breaks each calculation down into a repeatable step-by-step process that students can confidently apply in exams.

Inside you'll find:

✓ Titration and back-titration calculations
✓ Rate equations, orders and rate constant (k) calculations
✓ Gibbs free energy (ΔG) calculations
✓ Buffer pH calculations
✓ Arrhenius equation calculations

Complete with:
✓ Fully worked exam-style examples
✓ Typical A/A* model answers with examiner-focused commentary
✓ Common mistakes that cost marks and how to avoid them
✓ Key formulae and exam techniques for each topic

Designed specifically for A-Level Chemistry students, this guide helps turn complex calculations into a structured process that can be repeated under exam pressure.

Perfect for students aiming to improve confidence, accuracy and exam performance in one of the most heavily tested areas of the specification.

Organic mechanisms are one of the most heavily examined areas of A-Level Chemistry and a major source of lost marks for otherwise capable students. Mechanisms can account for up to 50% of A-Level Paper 2 Exams.

Suitable for OCR and AQA exam boards.

This guide breaks down every core A-Level mechanism into simple, repeatable patterns, helping you understand why each step happens rather than relying on memorisation alone.

Inside you'll find:

✓ Free-radical substitution
✓ Electrophilic addition
✓ Nucleophilic substitution
✓ Nucleophilic addition
✓ Electrophilic substitution

✓ Elimination

Complete with:
✓ Reagents and conditions glossary
✓ Colour-coded curly arrow mechanisms

✓ Drawing curly arrow mechanisms checklist

Designed for A-Level Chemistry students aiming to improve confidence, accuracy and exam technique, this guide provides a structured approach you can apply across Paper 2 and beyond.

Created by Ope Johnson - A-Level Chemistry exam technique specialist with 15+ years of tutoring experience helping students improve confidence, exam technique and grades.

If you're revising for OCR A A-Level Chemistry, you’ve probably wondered: What topics actually come up every year? After analysing the past five years of exam papers, I’ve identified the 10 most frequently examined topics - and I’ve highlighted quick-to-digest takeaways for each topic based on what examiners want you to know. Each topic ends with:

1. An A* model answer to a typical question you might encounter

2. Common mistakes that cost marks and how to avoid them

3. Examiner-led commentary of how to score highly

so you can study smarter and score higher. Whether you're aiming for an A* or just trying to boost your confidence, this guide is a starting point to revising strategically.

Please note that I do not make any guarantees of future exam questions and this compilation is based solely on historical trends