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
Energy Changes
Everyday uses, and investigating temperature change
- 3 things to know
- Chemistry Paper 1
Overview
Thermal decomposition and the citric acid and sodium hydrogencarbonate reaction, cold packs, hand warmers, reading energy change from a thermometer, and measuring temperature change in an insulated cup with the variables controlled.
What you need to know
Answer each one before you reveal it.
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Key term
Give one everyday application of an endothermic reaction.
Key term
A reaction mixture becomes noticeably colder as it proceeds. State what this tells you about the direction of the energy transfer.
Questions from this subtopic
Each one with the model answer underneath.
- 1
Name the type of reaction in which a substance is broken down by heating and which takes in energy from its surroundings.
Model answer
Thermal decomposition.
- 2
Which two substances are mixed in a well known endothermic reaction that makes the temperature of the mixture fall?
Model answer
Citric acid and sodium hydrogencarbonate.
- 3
Give one everyday application of an endothermic reaction.
Model answer
Some sports injury packs, which take in energy and so become cold.
- 4
Explain why an endothermic reaction is useful in a cold pack for a sports injury.
Model answer
It takes in energy from the surroundings, so the pack becomes cold and cools the injured area.
- 5
A reaction mixture becomes noticeably colder as it proceeds. State what this tells you about the direction of the energy transfer.
Model answer
Energy is being taken in from the surroundings, so the reaction is endothermic.
- 6
Why does a thermometer standing in a reaction mixture tell you about the energy change of the reaction?
Model answer
It records the temperature of the surroundings of the reacting particles, which rises when energy is given out and falls when energy is taken in.
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