GuidesChemistryPaper 2 · last-minute revision
3 days to go

GCSE Chemistry Edexcel Paper 2: last-minute revision

Three days left. Paper 2 covers energy changes, rates, organic chemistry, chemical analysis, the atmosphere and using resources, plus Topic 1 Key Concepts carries in from Paper 1. Get rates and organic chemistry locked first, they carry the most consistent marks.

Edexcel 1CH0
The plan

Your 3-day plan

One focus per day, building to a timed run. Work it in order.

3
3 days to go

Rates of reaction and the required practical it's built around

  • Learn the factors that increase rate (temperature, concentration, pressure, surface area, catalysts) and explain each one using collision theory: more frequent, more energetic collisions.
  • Practise drawing tangents on a rate graph, reading off the gradient, and calculating rate from it. This is one of the more technically demanding skills on the paper.
  • Redo energy changes: exothermic and endothermic reaction profiles, activation energy, and calculating overall energy change from bond energies (energy in minus energy out).
2
2 days to go

Required practicals: energy changes, rate of reaction, chromatography

  • Energy changes: practise plotting temperature-against-time graphs, drawing two lines of best fit, and extrapolating back to find the maximum temperature change.
  • Rate of reaction: practise the gas-collection or precipitation method and know how the graph changes shape for a lower concentration (less steep, plateaus at the same total volume for gas collection).
  • Chromatography: learn to calculate Rf value (distance moved by spot divided by distance moved by solvent) and explain what makes a good solvent choice for separating a mixture.
1
1 day to go

Light review: organic chemistry, atmosphere and resources recall

  • Skim your Knowledge Organisers for cracking, polymers and the greenhouse effect. These come up regularly but rarely need new learning this close to the exam.
  • Recap the Haber process and Le Chatelier's principle: if you increase pressure, equilibrium shifts to the side with fewer gas moles; if you increase temperature, it shifts in the endothermic direction.
  • Do one timed past-paper question on a 6-mark extended answer to check your structure is sharp, since Topic 1 content can carry in unexpectedly on this paper.
Priority order

The topics that come up most

Ranked from analysed past papers. Start at the top: if you run out of time, you will have covered the most-tested ground.

1

Factors Affecting Rate

Topic 7 Rates of Reaction and Energy Changes is guaranteed content every series, tied to the rate of reaction required practical. Explaining rate changes using collision theory is consistently tested.

2

Exothermic and Endothermic Reactions

Also part of Topic 7. Reaction profile diagrams and bond energy calculations recur every series, often linked to the energy changes required practical.

3

Cracking, Alkanes and Alkenes

Topic 8 Fuels and Earth Science and Topic 9 Hydrocarbons. Cracking conditions and the bromine water test for alkenes are a reliable source of marks most series.

4

Polymers

Part of Topic 9. Addition polymerisation and the difference between thermosoftening and thermosetting polymers are common short-answer targets.

5

The Greenhouse Effect and Climate Change

Topic 8 Fuels and Earth Science. The evidence linking human activity to climate change and evaluating solutions are frequently tested as extended-response questions.

6

Chromatography

Topic 9 Separate Chemistry 2 Qualitative Analysis. Rf value calculations and interpreting chromatograms recur reliably, tied to the required practical.

7

The Haber Process and Equilibrium

Topic 5 Dynamic Equilibria carries into Paper 2 content on industrial processes. Le Chatelier's principle applied to the Haber process is a recurring application question.

8

Recycling and Life Cycle Assessment

Topic 8 material covers using resources. Evaluate-style questions comparing recycling with new production, or comparing materials using a life cycle assessment, are a recurring extended answer.

Cheat sheet

Exam technique

Rules specific to Paper 2. On this paper, structure earns as many marks as knowledge.

1

Rate calculation method card

Rate = amount of product or reactant divided by time. If asked to find rate from a graph, draw a tangent at the point given, calculate the gradient (change in y divided by change in x), and give your answer with the correct unit. Show every step.

2

Bond energy calculations: energy in minus energy out

Add up the bond energies broken in the reactants (energy in), add up the bond energies formed in the products (energy out), then subtract. A negative answer means the reaction is exothermic, a positive answer means endothermic. State which one your answer shows.

3

Le Chatelier's principle in one line

A change in condition shifts equilibrium to oppose that change: increase pressure shifts to the side with fewer gas molecules; increase temperature shifts in the endothermic direction; increase concentration of a reactant shifts to produce more product.

4

Topic 1 content can carry into Paper 2 unexpectedly

Edexcel assesses Topic 1 Key Concepts on both papers. If a Paper 2 question needs a mole calculation, an equation to be balanced, or a bonding explanation, treat it exactly like a Paper 1 question, don't assume it won't appear here.

5

Evaluate questions on materials or processes need both sides

For 'evaluate' or 'compare' questions on recycling, life cycle assessment, or choosing a material, give at least one advantage and one disadvantage for each option, then finish with a clear conclusion that states which is better and why.

Avoid these

5 mistakes that cost marks

The errors examiners see most on this paper. Each one is an easy mark you already know how to keep.

Explaining rate changes without using collision theory languageAlways say collisions become more frequent and/or more energetic. 'Particles move faster' alone doesn't get full marks.

Getting the direction of an equilibrium shift wrong under increased pressureIncreasing pressure always shifts equilibrium to the side with fewer moles of gas. Count the moles on each side of the equation before deciding.

Mixing up which value to subtract from which in a bond energy calculationAlways do energy to break bonds in reactants, minus energy released forming bonds in products. Check your sign matches whether you expect the reaction to be exothermic or endothermic.

Assuming Topic 1 content (moles, bonding, equations) won't come up on Paper 2Topic 1 Key Concepts is examinable on both papers. Keep your moles method and equation-balancing skills sharp right up to this exam too.

Writing one-sided answers to 'evaluate' questions on recycling or life cycle assessmentStructure every evaluate answer as: point for, point against, then a conclusion that directly answers the question.

Exam day

The morning of the exam

The 60 minutes before you walk in. Review what you know and settle your nerves.

  • Read through your Knowledge Organisers for rates, energy changes, and the Haber process one final time.
  • Recap the bond energy rule out loud: energy in to break bonds, minus energy out forming bonds.
  • Check your calculator works and you're confident finding a gradient from a graph.
  • Highlight command words as you read each question: describe, explain, evaluate mean different things.
  • Eat something before you go in. You'll need concentration for multi-step calculations and longer evaluate answers.
  • Arrive with time to spare so you're calm, not rushed, going into the exam room.

Now test yourself

The 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.

Practise Chemistry questions

Start the 3-day plan now

Open the Chemistry Knowledge Organisers, quiz every priority topic and walk in ready. Free during alpha.

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