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 neutralisationThe process of electrolysis, and molten ionic compoundsUsing electrolysis to extract metalsElectrolysis of aqueous solutions
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
The Rate and Extent of Chemical Change
Collision theory and activation energy
- 3 things to know
- Chemistry Paper 2
Overview
The two conditions for colliding particles to react and activation energy, what collision theory explains, why higher concentration, gas pressure, surface area and temperature make collisions more frequent or more energetic, surface area to volume ratio, predicting rate changes when conditions are altered, and the symbols for proportionality, much less than, much greater than and approximately.
What you need to know
Answer each one before you reveal it.
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Key term
Explain why not every collision between reacting particles produces a reaction.
Key term
Explain, using collision theory, why increasing the pressure of reacting gases increases the rate of reaction.
Questions from this subtopic
Each one with the model answer underneath.
- 1
State the two conditions that must be met when reacting particles meet if a reaction is to happen.
Model answer
The particles must collide with each other, and the collision must have enough energy.
- 2
Define the activation energy of a reaction.
Model answer
It is the minimum amount of energy that particles must have in order to react when they collide.
- 3
State what collision theory is used to explain.
Model answer
It explains how factors such as concentration, pressure, surface area and temperature affect the rate of a reaction.
- 4
Explain why not every collision between reacting particles produces a reaction.
Model answer
Many collisions have less energy than the activation energy, so the particles simply bounce apart without reacting.
- 5
Explain, using collision theory, why increasing the concentration of a solution increases the rate of reaction.
Model answer
There are more reacting particles in the same volume of solution, so collisions between them are more frequent.
- 6
Explain, using collision theory, why increasing the pressure of reacting gases increases the rate of reaction.
Model answer
The same number of gas particles is squeezed into a smaller volume, so the particles are closer together and collide more frequently.
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