Key term
AQA GCSE Combined Science Chemistry 8464
Atomic Structure and the Periodic Table
Topic overviewAtoms, elements and compoundsWord equations, symbols and balanced equationsMixturesFrom the plum pudding model to the nuclear modelBohr, Chadwick and the modern model of the atomRelative electrical charges of subatomic particlesSize and mass of atomsRelative atomic mass and electronic structureThe periodic tableDevelopment of the periodic tableMetals and non-metalsGroup 0Group 1Group 7
Bonding, Structure, and the Properties of Matter
Topic overviewChemical bonds, including metallic bondingIonic bondingIonic compoundsCovalent bonding and how it is representedThe three states of matter and changes of statePredicting state, state symbols, and the limits of the particle modelProperties of ionic compoundsProperties of small moleculesPolymers and giant covalent structuresProperties of metals and alloys, and why metals conductDiamond and graphiteGraphene and fullerenes
Chemical Analysis
Chemical Changes
Topic overviewThe reactivity seriesMetal oxides, extraction, and redox in terms of electronsAcids reacting with metals, neutralisation and saltsSoluble saltsThe pH scale and neutralisationStrong and weak acidsThe process of electrolysis, and molten ionic compoundsUsing electrolysis to extract metalsElectrolysis of aqueous solutionsRepresentation of reactions at electrodes as half equations
Chemistry of the Atmosphere
Topic overviewThe Earth's early atmosphereHow oxygen increased and carbon dioxide decreasedThe gases in today's atmosphere, and which are greenhouse gasesHuman activities which contribute to an increase in greenhouse gases in the atmosphereGlobal climate change and carbon footprintsAtmospheric pollutants from fuels, and their effects
Energy Changes
Organic Chemistry
Quantitative Chemistry
The Rate and Extent of Chemical Change
Topic overviewMeasuring the mean rate of a reactionRate from graphs, and the gradient of a tangentFactors which affect the rates of chemical reactionsCollision theory and activation energyCatalystsReversible reactions and dynamic equilibriumThe effect of changing conditions on equilibriumThe effect of changing concentrationThe effect of temperature changes on equilibriumThe effect of pressure changes on equilibrium
Chemical Analysis
- 4 subtopics
- 12 things to know
- Chemistry Paper 2
What Chemical Analysis covers
Chemical Analysis is examined in Chemistry Paper 2. It covers pure substances, formulations, chromatography and tests for hydrogen, oxygen, carbon dioxide and chlorine.
Where it is assessed
Chemistry Paper 2
Combined Science: Trilogy, Chemistry Paper 2: 1 hour 15 minutes, 70 marks, 16.7% of the qualification.
Check the AQA specification ↗The 4 subtopics
Each one has its own page.
- Pure substancesThe chemical meaning of a pure substance, why pure substances melt and boil at fixed temperatures while mixtures change state over a range, using melting and boiling points to test purity, and the everyday meaning of pure compared with the chemist's.Open →
- FormulationsWhat a formulation is and why its components are measured in controlled quantities, the purpose of each ingredient, examples such as paints, medicines, cleaning agents, fertilisers, fuels, alloys and food sauces, and telling a formulation from a single compound or a natural mixture.Open →
- ChromatographyThe stationary and mobile phases, what decides how far a substance travels, how Rf values are defined and calculated, reading purity from a chromatogram, and why the start line is pencil and the solvent starts below it.Open →
- Tests for hydrogen, oxygen, carbon dioxide and chlorineThe burning splint test for hydrogen, the glowing splint test for oxygen, limewater turning milky for carbon dioxide, damp litmus paper bleached white by chlorine, why each test is carried out as it is, and identifying a gas from the result.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Describe the test for chlorine gas, the result seen, and why the litmus paper is moistened first.
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In chemical terms, what is meant by a pure substance?
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What is a formulation?
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What are the two phases involved in any form of chromatography?
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What is the difference between the way a pure compound changes state and the way a mixture does?
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What is true of every individual chemical in a formulation?
Evaluation
What decides how far a substance travels during chromatography?
Key term
State the measurement you would take to check whether a solid sample is pure.
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Name three household products that are formulations.
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How is the Rf value of a compound defined?
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Describe the test for hydrogen gas and the result you would see.
Take Chemical Analysis further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Stationary phase vs Mobile phase
Stationary phase: the part of a chromatography set-up that stays still, such as the paper. Mobile phase: the solvent that moves through and carries the substances along.
Pure substance vs Formulation
Pure substance: a single element or compound with nothing else mixed in. Formulation: a mixture designed with measured components to make a useful product.
Questions from this topic
Each one with the model answer underneath.
- 1
In chemical terms, what is meant by a pure substance?
Model answer
A pure substance is a single element or a single compound with nothing else mixed into it.
- 2
A sample contains molecules of one compound and nothing else. Is it pure in the chemical sense?
Model answer
Yes, because it is a single compound that is not mixed with any other substance.
- 3
Why is filtered sea water not a pure substance to a chemist?
Model answer
It is still a mixture of water and dissolved salts, so it is not a single element or compound.
- 4
What is the difference between the way a pure compound changes state and the way a mixture does?
Model answer
A pure compound melts and boils at specific fixed temperatures, while a mixture melts and boils over a range of temperatures.
- 5
State the measurement you would take to check whether a solid sample is pure.
Model answer
Measure its melting point and compare it with the accepted melting point of the pure substance.
- 6
Explain why a pure element melts at one sharp temperature.
Model answer
All of its particles are identical, so they all need the same amount of energy to break free at the same temperature.
What is inside Levo
Six ways to work the same material.
Chemical Analysis revision questions
- What does Chemical Analysis cover in AQA GCSE Combined Science Chemistry?
- 4 subtopics: pure substances, formulations, chromatography and tests for hydrogen, oxygen, carbon dioxide and chlorine. Each one has its own page with questions and model answers.
- How is Chemical Analysis organised?
- By the AQA 8464 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Chemical Analysis, on a schedule.
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