Numbers
AQA A-Level Chemistry 7405
Atomic Structure
Topic overviewFundamental ParticlesMass Number and IsotopesTime of Flight Mass Spectrometry: Ionisation and AccelerationTime of Flight Mass Spectrometry: Drift, Detection and Calculating m/zElectron Configuration: Sub-shells and OrbitalsElectron Configuration: Writing Configurations for Atoms and IonsIonisation Energies and Periodic Trends
Amount of Substance
Topic overviewRelative Atomic and Molecular MassThe Mole and the Avogadro ConstantThe Ideal Gas EquationEmpirical and Molecular FormulaBalanced Equations and Reaction CalculationsAtom Economy and Percentage YieldAcid-Base Titrations: Principles, Indicators and ApparatusAcid-Base Titrations: Standard Solutions and Calculations
Bonding
Topic overviewIonic BondingCovalent, Dative Covalent and Metallic BondingCrystal Structures: Giant Ionic Lattices and DiamondCrystal Structures: Graphite and Simple Molecular SolidsShapes of Molecules and Ions: VSEPR and Electron Pair RepulsionShapes of Molecules and Ions: Predicting Shapes and Bond AnglesElectronegativity and Bond PolarityIntermolecular Forces
Energetics and Thermodynamics
Kinetics
Topic overviewCollision Theory and Activation EnergyMaxwell-Boltzmann Distribution and the Effect of TemperatureEffect of Concentration and Pressure, and CatalystsRate Equations: The Rate Equation and Orders of ReactionRate Equations: The Effect of Concentration on RateThe Rate Constant and the Arrhenius EquationDetermining Rate Equations: The Initial Rates MethodDetermining Rate Equations: Continuous MonitoringRate Equations and Reaction Mechanisms
Chemical Equilibria
Redox and Electrochemistry
Topic overviewRedox: Definitions and the Rules for Oxidation StatesRedox: Identifying Oxidation and Reduction in a ReactionHalf-Equations and Combined Redox EquationsStandard Electrode Potentials and the Hydrogen ElectrodeElectrochemical Cells and EMF CalculationsPredicting Redox Reactions from Electrode PotentialsCommercial Cells and Fuel Cells
Acids and Bases
Periodicity and Group Chemistry
Topic overviews, p, d and f Block ClassificationTrends in Period 3Group 2 Trends in Atomic Radius, Ionisation Energy and Melting PointReactions of Group 2 with WaterSolubility Trends of Group 2 HydroxidesSolubility Trends of Group 2 SulfatesUses of Group 2 CompoundsTest for Sulfate IonsTrends in Electronegativity and Boiling Point of HalogensHalogens as Oxidising Agents and Displacement ReactionsHalide Ions as Reducing Agents: Chloride and BromideHalide Ions as Reducing Agents: Iodide, and the EquationsTest for Halide Ions Using Silver NitrateTests for Ammonium, Group 2, Hydroxide and Carbonate IonsReactions of Chlorine with WaterReactions of Chlorine with Cold Dilute NaOH and Water Treatment
Period 3 Elements and Their Oxides
Topic overviewReactions of Na and Mg with WaterPeriod 3 Elements with Oxygen: The Oxides Formed and Their BondingPeriod 3 Elements with Oxygen: Structures and Oxidation StatesMelting Points of Period 3 OxidesPeriod 3 Oxides with Water: Sodium and Magnesium OxidesPeriod 3 Oxides with Water: The Acidic Oxides and the pH TrendPeriod 3 Oxides with Acids and Bases: The ReactionsPeriod 3 Oxides with Acids and Bases: Acidic, Basic and Amphoteric
Transition Metals
Topic overviewGeneral Properties of Transition MetalsComplex Ions: Ligands, Coordinate Bonds and DenticityComplex Ions: Why a Species Can Act as a Ligand, and Coordination NumberSubstitution Reactions with Monodentate LigandsSubstitution Reactions with Bidentate and Multidentate LigandsHaemoglobin and the Chelate EffectShapes of Complex Ions and StereoisomerismFormation of Coloured Ions and the d-d TransitionColorimetry and Concentration DeterminationVariable Oxidation States and Vanadium ChemistryTollens' Reagent and Redox TitrationsHeterogeneous CatalysisVanadium(V) Oxide and the Contact ProcessHomogeneous Catalysis and AutocatalysisMetal-Aqua Ions and AcidityMetal Aqua Ions with Bases: Reactions with Hydroxide and AmmoniaMetal Aqua Ions with Bases: Why They React, and Their EquationsAmphoteric HydroxidesIdentifying Transition Metal Ions by Test-Tube Reactions
Introduction to Organic Chemistry
Hydrocarbons
Topic overviewAlkanes, Fractional Distillation and CrackingCombustion of Alkanes and PollutantsFree Radical Chlorination of AlkanesAlkenes: Structure, Bonding and Electrophilic AdditionMarkovnikov's Rule and Carbocation StabilityAddition Polymers and Repeating UnitsProperties and Uses of Polyalkenes
Halogenoalkanes, Alcohols and Organic Analysis
Topic overviewNucleophilic Substitution of HalogenoalkanesEffect of Bond Enthalpy on Reaction RateElimination Reactions and Competing MechanismsCFCs and Ozone DepletionIndustrial Production of AlcoholsBiofuels and Carbon NeutralityClassification and Oxidation of AlcoholsDistinguishing Aldehydes and KetonesElimination of Water from AlcoholsTest-Tube Reactions for Functional GroupsMass Spectrometry and Molecular FormulaInfrared Spectroscopy, Functional Groups and Global Warming
Carbonyls, Carboxylic Acids and Derivatives
Topic overviewOxidation of Aldehydes and Distinguishing TestsReduction of Carbonyls with NaBH4Nucleophilic Addition with KCN and Hydroxynitrile FormationHazards of KCN and Formation of EnantiomersStructure and Acidity of Carboxylic AcidsEsterification and the Uses of EstersVegetable Oils, Fats and the Hydrolysis of EstersSoap and Biodiesel Production from FatsStructure of Acid Anhydrides, Acyl Chlorides and AmidesNucleophilic Addition-Elimination Reactions of Acyl ChloridesAcid Anhydrides and the Industrial Synthesis of AspirinPurifying organic solids and liquids
Aromatic Chemistry and Amines
Topic overviewBonding and Stability of BenzeneElectrophilic Substitution: NitrationElectrophilic Substitution: Friedel-Crafts AcylationPreparation of Aliphatic and Aromatic AminesBase Strength of AminesAmines as Nucleophiles, and Quaternary Ammonium SaltsAmines with Acyl Chlorides and Acid Anhydrides
Polymers, Amino Acids, Proteins and DNA
Topic overviewCondensation Polymers: PolyestersCondensation Polymers: PolyamidesIntermolecular Forces in Condensation PolymersBiodegradability and Disposal of PolymersAmino Acids and ZwitterionsPeptide Bonds and Protein StructureHydrogen Bonding and Disulfide Bridges in ProteinsHydrolysis of Proteins and TLC IdentificationEnzymes, Active Sites and Inhibitors in Drug DesignDNA: Nucleotides, the Double Helix and Base PairingCisplatin and Anticancer Drug Action
Organic Synthesis, NMR and Chromatography
Topic overviewMulti-Step Synthesis RoutesGreen Chemistry Principles in Synthesis DesignPrinciples of NMR and the Delta ScaleCarbon-13 NMR InterpretationProton NMR Chemical Shift and IntegrationSpin-Spin Splitting and the n+1 RuleTMS and Deuterated SolventsThin-Layer Chromatography and Rf ValuesColumn and Gas Chromatography, and GC-MS
Amount of Substance
- 8 subtopics
- 24 things to know
- Papers 1, 2 and 3
What Amount of Substance covers
Amount of substance is examined on Papers 1, 2 and 3, and is the topic every calculation in the specification leans on. It runs from relative masses and the mole through gas volumes, formulae, yields and titrations.
Where it is assessed
Papers 1, 2 and 3
Physical chemistry drawn on by both written papers.
Check the AQA specification ↗The 8 subtopics
Each one has its own page.
- Relative Atomic and Molecular MassWhat relative atomic and molecular mass mean, and why carbon-12 is the standard.Open →
- The Mole and the Avogadro ConstantThe mole, the Avogadro constant, and converting between mass, moles and particles.Open →
- The Ideal Gas EquationpV = nRT, the units each term must be in, and using it to find moles or molar mass.Open →
- Empirical and Molecular FormulaWorking out empirical formula from composition, and scaling it to the molecular formula.Open →
- Balanced Equations and Reaction CalculationsBalancing equations and using the ratios in them to work out reacting masses.Open →
- Atom Economy and Percentage YieldCalculating both, telling them apart, and why industry cares about each.Open →
- Acid-Base Titrations: Principles, Indicators and ApparatusWhat a titration measures, choosing an indicator, and the apparatus and technique that make the result reliable.Open →
- Acid-Base Titrations: Standard Solutions and CalculationsMaking up a standard solution, and working concentration out from titre using moles = concentration × volume.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What formula relates the concentration, volume, and number of moles of a solution?
Key term
What is the formula relating moles, concentration and volume?
Numbers
A burette has an uncertainty of ±0.05 cm³ per reading. Calculate the percentage uncertainty in a titre of 25.00 cm³.
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What is relative atomic mass?
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What is the Avogadro constant?
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What does the Avogadro constant represent?
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State the ideal gas equation.
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What does n represent in the ideal gas equation?
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What is the definition of empirical formula?
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What is the definition of molecular formula?
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What must be conserved in a balanced chemical equation?
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What is the formula for calculating atom economy?
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Why is atom economy an important consideration in industrial chemistry?
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What type of reaction is typically involved in an acid-base titration?
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What is the equivalence point in a titration?
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What standard is used as the reference for relative atomic mass?
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To what types of particles can the mole be applied?
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What does R represent in the ideal gas equation?
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How does the molecular formula relate to the empirical formula?
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In terms of atoms, what does balancing a chemical equation ensure?
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What type of reaction has 100% atom economy?
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What is the difference between the equivalence point and the end point of a titration?
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How do you convert volume in cm³ to volume in dm³?
Take Amount of Substance further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Empirical formula vs Molecular formula
Empirical formula: simplest whole-number ratio of atoms of each element. Molecular formula: actual number of atoms of each element in one molecule.
Percentage yield vs Atom economy
Percentage yield: actual product amount divided by theoretical product amount, multiplied by one hundred. Atom economy: desired product formula mass divided by all product formula masses, multiplied by one hundred.
Standard solution vs Stock solution
Standard solution: a solution with an accurately known concentration. Stock solution: a concentrated solution used to prepare more dilute solutions.
Questions from this topic
Each one with the model answer underneath.
- 1
What is relative atomic mass?
Model answer
The weighted mean mass of an atom of an element relative to one-twelfth of the mass of an atom of carbon-12.
- 2
What standard is used as the reference for relative atomic mass?
Model answer
One-twelfth of the mass of an atom of carbon-12.
- 3
Why is carbon-12 used as the standard for relative atomic mass?
Model answer
Carbon-12 is a stable isotope with a precisely defined mass, providing a consistent reference standard.
- 4
What is relative molecular mass?
Model answer
The weighted mean mass of a molecule relative to one-twelfth of the mass of an atom of carbon-12.
- 5
How is relative molecular mass calculated from a molecular formula?
Model answer
By adding together the relative atomic masses of all atoms present in the molecular formula.
- 6
What is relative formula mass?
Model answer
The weighted mean mass of a formula unit relative to one-twelfth of the mass of an atom of carbon-12.
What is inside Levo
Six ways to work the same material.
Amount of Substance revision questions
- What does Amount of Substance cover in AQA A-Level Chemistry?
- 8 subtopics: relative atomic and molecular mass, the mole and the avogadro constant, the ideal gas equation, empirical and molecular formula, balanced equations and reaction calculations, atom economy and percentage yield, acid-base titrations: principles, indicators and apparatus and acid-base titrations: standard solutions and calculations. Each one has its own page with questions and model answers.
- How is Amount of Substance organised?
- By the AQA 7405 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Amount of Substance, 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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