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
The Rate and Extent of Chemical Change
Catalysts
- 3 things to know
- Chemistry Paper 2
Overview
What a catalyst is and why little is needed, why different reactions need different catalysts, enzymes as biological catalysts, how a catalyst provides a pathway with lower activation energy without changing the amount of product or the energy change, its effect on a reaction profile, identifying one, and industrial uses.
What you need to know
Answer each one before you reveal it.
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Key term
Explain why only a small amount of a catalyst is needed even for a reaction that is run many times.
Key term
Describe how the reaction profile of a catalysed reaction differs from that of the same reaction without a catalyst.
Questions from this subtopic
Each one with the model answer underneath.
- 1
Define a catalyst.
Model answer
A catalyst is a substance that changes the rate of a chemical reaction without being used up in the reaction.
- 2
Explain why only a small amount of a catalyst is needed even for a reaction that is run many times.
Model answer
The catalyst is not used up during the reaction, so the same catalyst can be used over and over again.
- 3
State whether one catalyst will speed up any chemical reaction.
Model answer
No, different reactions need different catalysts.
- 4
Name the substances that act as catalysts in living organisms.
Model answer
Enzymes.
- 5
Explain why enzymes are described as catalysts.
Model answer
They speed up reactions in biological systems and are not used up by those reactions.
- 6
Explain how a catalyst increases the rate of a chemical reaction.
Model answer
It provides a different pathway for the reaction that has a lower activation energy.
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