Key term
AQA GCSE Chemistry 8462
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 7Transition metals, and how they differ from Group 1
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 fullerenesSizes of particles and their propertiesUses of nanoparticles
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 neutralisationTitrationsStrong 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
Topic overviewCrude oil, hydrocarbons and alkanesFractional distillation and petrochemicalsProperties of hydrocarbonsCracking, and testing alkenes with bromine waterWhy cracking is useful, and equations for itStructure and formulae of alkenesReactions of alkenesAlcoholsCarboxylic acidsAddition polymerisationCondensation polymerisationAmino acids, DNA and naturally occurring polymers
Quantitative Chemistry
Topic overviewConservation of mass and balanced chemical equationsRelative formula mass and concentration of solutionsMass changes when a gas is involved, and measurement uncertaintyMolesAmounts of substances in equations, and balancing using molesLimiting reactantsPercentage yieldAtom economyUsing concentrations of solutions in mol/dmUse of amount of substance in relation to volumes of gases
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
Using Resources
Topic overviewUsing the Earth's resources and sustainable developmentProducing potable water in the UKDesalination, and analysing water samplesWaste water treatmentAlternative methods of extracting metalsLife cycle assessmentWays of reducing the use of resourcesCorrosion and its preventionAlloys as useful materialsGlass, clay ceramics and polymersComposites, and comparing materialsThe Haber processProduction and uses of NPK fertilisers
Chemical Changes
Strong and weak acids
- 3 things to know
- Paper 1
Overview
Strong acids as completely ionised and weak acids as partially ionised, examples of each, why a strong acid has a lower pH than a weak acid of the same concentration, the tenfold change in hydrogen ion concentration per pH unit, concentrated and dilute acids, and neutrality at pH 7.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Evaluation
Explain the difference between a concentrated acid and a dilute acid, and how the strength of an acid differs from its concentration.
Key term
Name three strong acids.
Questions from this subtopic
Each one with the model answer underneath.
- 1
What does it mean to say that an acid is strong?
Model answer
It is completely ionised when it is dissolved in water.
- 2
Name three strong acids.
Model answer
Hydrochloric acid, nitric acid and sulfuric acid.
- 3
What happens to essentially every hydrogen chloride molecule when it dissolves in water?
Model answer
It splits up completely, releasing a hydrogen ion and a chloride ion.
- 4
What does it mean to say that an acid is weak?
Model answer
It is only partially ionised when it is dissolved in water.
- 5
Name three weak acids.
Model answer
Ethanoic acid, citric acid and carbonic acid.
- 6
Explain why only a small fraction of the ethanoic acid molecules in a solution release hydrogen ions.
Model answer
Ethanoic acid is a weak acid, so its ionisation is only partial and most of the molecules stay intact.
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