Three days left. Paper 2 covers C4 to C6: Chemical Patterns, Chemical Analysis, and Making Useful Chemicals, and it includes two 6-mark extended answers. Get the analysis tests and rate calculations locked first.
One focus per day, building to a timed run. Work it in order.
Ranked from analysed past papers. Start at the top: if you run out of time, you will have covered the most-tested ground.
C5 Chemical Analysis is built around practical identification. The gas tests and ion tests are guaranteed recall marks that come up in some form every series.
C5 leans heavily on quantitative analysis. Titration calculations linking concentration, volume and moles are a recurring multi-mark question on this paper.
C6 Making Useful Chemicals is where rate of reaction content sits on OCR B. Collision theory explanations and rate calculations from graphs are consistently tested.
Also part of C6. Le Chatelier's principle applied to industrial processes is a common context for one of the two 6-mark extended answers on this paper.
C4 Chemical Patterns centres on explaining trends using electron structure. Group 7 reactivity and displacement reactions are a reliable source of marks.
Part of C5. Rf value calculations and interpreting chromatograms to assess purity are tested most series, often alongside a practical-method question.
Opens C4 and underpins the rest of the paper's explanations. Electron shell diagrams and linking configuration to group number are common early-paper marks.
C6 content that connects to reaction profiles and bond energy calculations. Sketching and labelling reaction profile diagrams correctly is a frequent short-answer target.
PrepWise has a one-page Knowledge Organiser for every topic above. Use them in your final 3 days with cover, recall, check, repeat: read it once, cover it, write out everything you remember, then check what you missed and go again.
Rules specific to Paper 2. On this paper, structure earns as many marks as knowledge.
'Bubble the gas through limewater; it turns milky' is a complete answer. Naming the gas alone, or describing the test without the result, only earns partial credit. Learn all four tests as fixed pairs.
Use moles = concentration multiplied by volume, converting cm³ to dm³ by dividing by 1000. Find moles of the known solution first, use the balanced equation for the mole ratio, then calculate what's asked. Show every step for method marks.
A change in condition shifts equilibrium to oppose that change: increase pressure shifts to the side with fewer gas moles; increase temperature shifts in the endothermic direction. State the direction and the reason together.
Before writing, jot down 3 to 4 key points in order. Markers reward a complete, logically sequenced answer with a clear conclusion over a longer answer that repeats itself or jumps between ideas.
For Group 7 reactivity, always reference the number of electron shells and the distance of the outer shell from the nucleus. A trend stated without the electron-based reason is an incomplete answer on OCR B.
The errors examiners see most on this paper. Each one is an easy mark you already know how to keep.
Naming a gas test result without describing what you'd actually see or hear → Learn the full observation for each test: hydrogen gives a squeaky pop with a lit splint, oxygen relights a glowing splint, carbon dioxide turns limewater milky, chlorine bleaches damp litmus paper.
Using cm³ instead of dm³ in a titration calculation → Always convert cm³ to dm³ by dividing by 1000 before using moles = concentration multiplied by volume.
Getting the direction of an equilibrium shift wrong under increased pressure → Increasing pressure always shifts equilibrium to the side with fewer moles of gas. Count the moles on each side of the equation before deciding, don't guess.
Explaining Group 7 reactivity trend as 'it just gets less reactive' with no reason → Always explain using electron shells: going down the group, the outer electron is further from the nucleus and more shielded, so it's harder to gain, making the halogen less reactive.
Writing an unstructured 6-mark answer that repeats the same point → Plan 3 to 4 distinct points before you start writing, then write them in a logical order ending with a conclusion that answers the question asked.
The 60 minutes before you walk in. Review what you know and settle your nerves.
The tests and calculations only stick once you have actually done them under pressure. Practise exam-style Chemistry questions in PrepWise, get instant marking, and turn those method cards into marks.
Open the Chemistry Knowledge Organisers, quiz every priority topic and walk in ready. Free during alpha.
Get started with your personalised revision