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
Chemical Changes
- 10 subtopics
- 30 things to know
- Chemistry Paper 1
What Chemical Changes covers
Chemical Changes is examined in Chemistry Paper 1. It covers the reactivity series, metal oxides, extraction, and redox in terms of electrons, acids reacting with metals, neutralisation and salts, soluble salts, the pH scale and neutralisation, strong and weak acids, the process of electrolysis, and molten ionic compounds, using electrolysis to extract metals, electrolysis of aqueous solutions and representation of reactions at electrodes as half equations.
Where it is assessed
Chemistry Paper 1
Combined Science: Trilogy, Chemistry Paper 1: 1 hour 15 minutes, 70 marks, 16.7% of the qualification.
Check the AQA specification ↗The 10 subtopics
Each one has its own page.
- The reactivity seriesMetals forming positive ions and reactivity as the tendency to do so, the series from potassium to copper with hydrogen and carbon for comparison, displacement reactions, ordering metals by their reactions with water and dilute acid in a fair test, and why potassium reacts more vigorously than magnesium.Open →
- Metal oxides, extraction, and redox in terms of electronsMetal oxides and oxidation and reduction in terms of oxygen, why gold is found as the metal, extracting metals less reactive than carbon by reduction with carbon, comparing extraction methods, and oxidation and reduction in terms of electrons, with ionic and half equations for displacement reactions.Open →
- Acids reacting with metals, neutralisation and saltsMetals reacting with dilute acids to give a salt and hydrogen, the test for hydrogen, these reactions as redox in terms of electrons, neutralisation of acids by alkalis, bases and metal carbonates, the difference between a base and an alkali, naming salts from their acids, and deducing salt formulae from their ions.Open →
- Soluble saltsMaking a soluble salt by adding an insoluble metal, oxide, hydroxide or carbonate to an acid in excess, filtering off the unreacted solid, crystallising and drying the salt, the copper sulfate preparation, choosing gentle heating, safety precautions, and why crystals can lose mass.Open →
- The pH scale and neutralisationHydrogen ions in acids and hydroxide ions in alkalis, aqueous solutions, the pH scale from 0 to 14 measured with universal indicator or a pH probe, acidic, neutral and alkaline values, and neutralisation as hydrogen ions reacting with hydroxide ions to form water, with its ionic equation.Open →
- Strong and weak acidsStrong 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.Open →
- The process of electrolysis, and molten ionic compoundsElectrolytes and why molten or dissolved ionic compounds conduct, electrolysis and the cathode and anode, which ions move to each electrode, what half equations show and what must balance in them, inert electrodes, and predicting the products of electrolysing molten lead bromide, sodium chloride and zinc bromide.Open →
- Using electrolysis to extract metalsWhen electrolysis is used to extract a metal, why the compound must be molten and why the process is costly, and the extraction of aluminium from aluminium oxide mixed with cryolite using carbon anodes that burn away.Open →
- Electrolysis of aqueous solutionsWhich ions are present in a solution, how relative reactivity decides whether the metal or hydrogen forms at the cathode, when oxygen or a halogen forms at the anode, predicting products, and testing the gases collected.Open →
- Representation of reactions at electrodes as half equationsWhy cathode reactions are reductions and anode reactions oxidations, half equations for metal ions, hydrogen ions, halide ions, oxide ions and hydroxide ions, balancing atoms and charge, and the two ways of writing an oxidation.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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Describe what happens when zinc or magnesium reacts with dilute hydrochloric acid and explain, in terms of electrons, why it is a redox reaction.
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Name three weak acids and explain why ethanoic acid has a higher pH than hydrochloric acid of the same concentration.
Evaluation
Explain the difference between a concentrated acid and a dilute acid, and how the strength of an acid differs from its concentration.
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What kind of ion does a metal atom form when it reacts with another substance?
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What type of compound is formed when a metal reacts with oxygen?
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Name four kinds of insoluble solid that can be added to an acid to make a soluble salt.
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Which ion do all acids produce when they dissolve in water?
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What is an electrolyte?
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When is electrolysis used to extract a metal from its compound?
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Why are the reactions taking place at the cathode described as reductions?
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List potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper in order from most reactive to least reactive.
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Write the balanced equation for magnesium burning in oxygen.
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Name the two products formed when a dilute acid reacts with a suitable metal.
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How is the unreacted solid separated from the salt solution?
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What does it mean to describe a solution as aqueous?
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Give two ways of turning a solid ionic compound into an electrolyte.
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Why must the compound be molten before its metal can be extracted by electrolysis?
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What decides which ions are discharged when a solution is electrolysed with inert electrodes?
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Write the half equation for lead ions being discharged at the cathode.
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Which two non-metals are often placed in the reactivity series?
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Define oxidation in terms of oxygen.
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Write a word equation for zinc reacting with dilute hydrochloric acid.
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When a soluble salt is made by adding an excess of insoluble solid to an acid and filtering, what is collected in the beaker below the funnel?
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Which ion is present in every aqueous solution of an alkali?
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Name three strong acids.
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What is electrolysis?
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Suggest why metals obtained by electrolysis tend to be expensive.
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Which ions are present in a solution made by dissolving a single ionic compound in water?
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Write the half equation for aluminium ions being discharged at the cathode.
Take Chemical Changes further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Oxidation vs Reduction
Oxidation: loss of electrons, or gain of oxygen, by a substance. Reduction: gain of electrons, or loss of oxygen, by a substance.
Cathode vs Anode
Cathode: the negative electrode, where positive ions gain electrons. Anode: the positive electrode, where negative ions lose electrons.
Strong acid vs Weak acid
Strong acid: one completely ionised when dissolved in water. Weak acid: one only partially ionised when dissolved in water.
Questions from this topic
Each one with the model answer underneath.
- 1
What kind of ion does a metal atom form when it reacts with another substance?
Model answer
A positively charged ion.
- 2
What is the reactivity of a metal related to?
Model answer
Its tendency to lose electrons and form positive ions.
- 3
List potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper in order from most reactive to least reactive.
Model answer
Potassium, sodium, lithium, calcium, magnesium, zinc, iron, copper.
- 4
Which two non-metals are often placed in the reactivity series?
Model answer
Hydrogen and carbon.
- 5
Why is carbon included in the reactivity series?
Model answer
So that metals can be compared with it, which shows whether carbon can take the oxygen from a metal oxide.
- 6
Why is hydrogen included in the reactivity series?
Model answer
So that metals can be compared with it, which shows whether a metal will react with a dilute acid to release hydrogen.
What is inside Levo
Six ways to work the same material.
Chemical Changes revision questions
- What does Chemical Changes cover in AQA GCSE Combined Science Chemistry?
- 10 subtopics: the reactivity series, metal oxides, extraction, and redox in terms of electrons, acids reacting with metals, neutralisation and salts, soluble salts, the ph scale and neutralisation, strong and weak acids, the process of electrolysis, and molten ionic compounds, using electrolysis to extract metals, electrolysis of aqueous solutions and representation of reactions at electrodes as half equations. Each one has its own page with questions and model answers.
- How is Chemical Changes organised?
- By the AQA 8464 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Chemical Changes, 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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