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
Organic Chemistry
- 5 subtopics
- 15 things to know
- Chemistry Paper 2
What Organic Chemistry covers
Organic Chemistry is examined in Chemistry Paper 2. It covers crude oil, hydrocarbons and alkanes, fractional distillation and petrochemicals, properties of hydrocarbons, cracking, and testing alkenes with bromine water and why cracking is useful, and equations for it.
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 5 subtopics
Each one has its own page.
- Crude oil, hydrocarbons and alkanesCrude oil as a finite resource formed from ancient plankton, hydrocarbons and why crude oil is a mixture, the alkanes and their general formula CₙH₂ₙ₊₂, the molecular formulae of methane, ethane, propane and butane, and what molecular and displayed formulae show.Open →
- Fractional distillation and petrochemicalsSeparating crude oil into fractions of similar-sized molecules by fractional distillation, fuels such as petrol, diesel and kerosene, petrochemical feedstock for solvents, lubricants, polymers and detergents, why carbon forms so many compounds, homologous series, and how the fractionating column works.Open →
- Properties of hydrocarbonsHow boiling point, viscosity and flammability depend on molecular size, what viscosity and flammability mean, complete combustion of hydrocarbons to carbon dioxide and water as an exothermic oxidation, balanced combustion equations for methane, ethane and propane, and choosing hydrocarbons as fuels.Open →
- Cracking, and testing alkenes with bromine waterCracking as the thermal decomposition of large hydrocarbons into smaller molecules, catalytic cracking and steam cracking and their conditions, the alkanes and unsaturated alkenes produced, and the bromine water test, which turns from orange to colourless with an alkene.Open →
- Why cracking is useful, and equations for itWhy small hydrocarbons are in demand and large fractions are cracked, the uses of alkenes, balancing cracking equations such as C₁₀H₂₂ to C₈H₁₈ and C₂H₄, and how modern life depends on hydrocarbons.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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Explain why the size of its molecules decides how a hydrocarbon is used as a fuel.
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What is crude oil formed from?
Process
What two broad kinds of useful product are made by processing the fractions of crude oil?
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Which fractions from crude oil are the most likely to be cracked, and why?
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Where is crude oil found today?
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What is meant by feedstock in the petrochemical industry?
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What is meant by the viscosity of a liquid?
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What is cracking?
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Explain why the numbers of carbon and hydrogen atoms must be the same on both sides of an equation for cracking.
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What is a hydrocarbon?
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Name three fuels produced from crude oil.
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What is meant by the flammability of a fuel?
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Explain why cracking one large hydrocarbon molecule always gives more than one product molecule.
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Give one example that illustrates the usefulness of cracking.
Take Organic Chemistry further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Alkane vs Alkene
Alkane: a saturated hydrocarbon with the general formula CₙH₂ₙ₊₂. Alkene: an unsaturated hydrocarbon containing a carbon–carbon double bond.
Catalytic cracking vs Steam cracking
Catalytic cracking: passing hydrocarbon vapour over a hot catalyst at high temperature. Steam cracking: mixing hydrocarbon vapour with water vapour at a very high temperature.
Questions from this topic
Each one with the model answer underneath.
- 1
What is crude oil formed from?
Model answer
Crude oil formed from the remains of an ancient biomass, mainly plankton, that was buried in mud.
- 2
Where is crude oil found today?
Model answer
Crude oil is found trapped in rocks underground.
- 3
Explain why crude oil is described as a finite resource.
Model answer
It took many millions of years to form and is being used far faster than it is replaced, so supplies will eventually run out.
- 4
Which organisms made up most of the ancient biomass that became crude oil?
Model answer
Plankton.
- 5
What is a hydrocarbon?
Model answer
A hydrocarbon is a molecule made up of hydrogen and carbon atoms only.
- 6
Explain why crude oil is classed as a mixture and not as a compound.
Model answer
It contains a very large number of different compounds that are not chemically bonded to one another.
What is inside Levo
Six ways to work the same material.
Organic Chemistry revision questions
- What does Organic Chemistry cover in AQA GCSE Combined Science Chemistry?
- 5 subtopics: crude oil, hydrocarbons and alkanes, fractional distillation and petrochemicals, properties of hydrocarbons, cracking, and testing alkenes with bromine water and why cracking is useful, and equations for it. Each one has its own page with questions and model answers.
- How is Organic Chemistry organised?
- By the AQA 8464 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Organic Chemistry, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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