In this post, I want to share some of my personal experience, as well as what I have learned from teaching students preparing for the Cambridge Chemistry Challenge.
When I prepared for the Cambridge Chemistry Challenge in 2023, one of the most important things I realised was that you do not necessarily need to know the entire AS and A2 Chemistry syllabus in advance. What matters more is having a very strong foundation in the core AS topics and being able to apply familiar ideas in unfamiliar situations. The paper is not simply testing how much chemistry you have memorised.
One distinctive feature of C3L6 is the amount of reading involved. Many questions are quite long and begin by introducing a new idea, providing some background information, or walking you through an example before asking you to apply that knowledge yourself. I think of these questions almost like a short chemistry lesson inside the exam: the paper teaches you something new, and your job is to understand it quickly enough to use it.
Because of this, reading ability and comprehension are extremely important. You need to be able to identify the useful information, understand what the question is trying to teach you, and then apply it correctly. The competition rewards adaptability. When you meet a concept, you have never seen before, you should not immediately think, “I don’t know this.” Instead, ask yourself: “What has the question already told me, and how can I use it?”
In terms of topic balance, C3L6 is also quite different from the UK Chemistry Olympiad. UKChO often contains a much larger amount of organic chemistry, whereas C3L6 generally places less emphasis on long organic mechanisms. From my own experience, it tends to favour questions involving molecular structure, bonding and isomerism more heavily.
The most important part of my preparation was still doing a large number of past papers. C3L6 has a very recognisable style, and the more papers you complete, the easier it becomes to recognise the patterns in how questions are structured and what type of reasoning they expect from you.
Once your C3L6 fundamentals are secure, I also think selected UKChO questions are very useful. UKChO is generally more difficult, but the way many of its questions are structured is quite similar: you are often given unfamiliar information and expected to work logically from it. Carefully selected UKChO questions can therefore be a very good way to push yourself beyond C3L6 level and become more comfortable with higher-difficulty problems.
From my teaching experience, I have found that students often improve most when they stop treating unfamiliar questions as something they are “not supposed to know” and instead learn to extract information from the question itself. Strong fundamentals, careful reading, and a lot of past-paper practice are, in my view, the three most important parts of preparing well for C3L6.