Chemical changes: GCSE Chemistry
Reactivity series, extracting metals, acids, salts, neutralisation and electrolysis
The short version
The reactivity series predicts displacement and how we extract metals. Neutralisation is acid + base. Electrolysis needs a molten or dissolved electrolyte and inert electrodes.
Key idea
Most reactive → least (C and H included for extraction)
Grade 2–3: A more reactive metal can push a less reactive metal out of its compound.
Grade 5–6: I can use acid fizz to put Mg, Zn and Cu in order, and I know gold is unreactive.
Grade 9: I write the ion-electron story for displacement and I never put potassium into copper sulfate as a school demo — exam questions still use the series on paper.
Go a bit deeper
Exam sentence: more reactive than carbon, so extracted by electrolysis
Grade 2–3: Iron can be made with carbon in a hot furnace. Aluminium needs a powerful electric current.
Grade 5–6: I can sort metals into carbon-reduction vs electrolysis and I know gold is native.
Grade 9: I name phytomining and bioleaching with one advantage (conserves high-grade ore) and one disadvantage (slow). Cryolite detail sits in the electrolysis lesson.
Worked example
Worked example
Grade 2–3: A more reactive metal can push a less reactive metal out of its compound. Grade 5–6: I can use acid fizz to put Mg, Zn and Cu in order, and I know gold is unreactive. Grade 9: I write the ion-electron story for displacement and I never put potassium into copper sulfate as a school demo — exam questions still use the series on paper.
Lessons in this topic
- The reactivity series
- Extraction of metals
- Acids, alkalis and salts
- Neutralisation
- Electrolysis of molten compounds
- Electrolysis of aqueous solutions
In the app each lesson is video (when we have a real YouTube id) then intro, learn and summary steps.
What the examiner wants
State the ion movement: cations to cathode (reduction), anions to anode (oxidation). For aqueous solutions, hydrogen or the metal may form at the cathode depending on reactivity.
Try these questions
Cover the answers and have a go first. Worked solutions are underneath.
Which metal is the most reactive?
Zinc displaces copper from copper sulfate because zinc is
A metal more reactive than carbon is extracted by
Phytomining extracts copper using
Common mistakes
- Do not say copper is unreactive because it is a metal. Reactivity is relative. "Bacteria get used to acid" is biology — here the metal either reacts or it does not.
- You cannot extract aluminium with carbon in a simple furnace in the same way — aluminium is more reactive than carbon.
- Concentrated is about moles per dm^3. Strong is about how fully it ionises. Say excess insoluble base, then filter — that method mark is often missed.
- Do not drink lab alkali to cancel acid. Everyday examples are carefully chosen weak bases in small amounts. Neutralisation warms slightly — it is exothermic.
Answers and working
Frequently asked questions
Is GCSE Chemical changes on Combined Science and Triple?
Chemical changes is on Combined Science and on Triple Chemistry. Progress is shared in the ReviseEasy app.
Which exam board is this Chemical changes page for?
The ideas are board-agnostic for AQA, Edexcel, OCR, WJEC and CCEA. Paper lengths and question numbers differ — check your specification.
Is Chemical changes Foundation or Higher?
The core ideas appear on both tiers. Higher papers add extra application and some HT-only detail, marked in lessons with a Higher badge.
Learn, try, get feedback, fix the mistake
Open the stepped lesson, then the quiz with hints. Required-practical and calculation questions use the same method you will need in the paper.
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