Key term
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
Acids and Bases
- 7 subtopics
- 21 things to know
- Papers 1 and 3
What Acids and Bases covers
Acids and bases is examined on Papers 1 and 3, and is the most calculation-heavy topic in physical chemistry. It runs from the Brønsted-Lowry definition through pH of strong and weak acids and bases to titration curves, indicators and buffers.
Where it is assessed
Papers 1 and 3
Inorganic and physical chemistry, then the synoptic paper.
Check the AQA specification ↗The 7 subtopics
Each one has its own page.
- Brønsted-Lowry Acid-Base EquilibriaAcids as proton donors and bases as proton acceptors, and identifying conjugate pairs in an equilibrium.Open →
- The pH Scale and Strong AcidspH as a logarithmic scale, and calculating pH of a strong acid and back again.Open →
- The Ionic Product of Water and Strong BasesKw, its value at 25°C, and using it to find the pH of a strong base.Open →
- Weak Acids and KaPartial dissociation, the Ka and pKa expressions, and calculating the pH of a weak acid.Open →
- pH Curves and Acid-Base TitrationsThe four curve shapes, locating the equivalence point, and reading pKa from the half-neutralisation point.Open →
- IndicatorsHow an indicator works, and choosing one whose range falls on the vertical section of the curve.Open →
- Buffer SolutionsWhat buffers are made from, how they resist pH change, and calculating the pH of one.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What is the pH of a 0.05 mol dm⁻³ solution of Ba(OH)₂ at 25°C?
Who and when
According to the Brønsted-Lowry theory, what is an acid?
Who and when
According to the Brønsted-Lowry theory, what is a base?
Key term
What does pH measure?
Key term
What is the mathematical definition of pH?
Key term
What is a weak acid?
Key term
What does it mean for a weak acid to be partially dissociated?
Key term
What is the typical shape of a pH curve for the titration of a strong acid with a strong base?
Key term
What is the typical shape of a pH curve for the titration of a weak acid with a strong base?
Key term
What is an acid-base indicator in terms of its chemical nature?
Key term
How does an indicator function during a titration?
Key term
What is a buffer solution?
Key term
What two components make up an acidic buffer solution?
Key term
What particle is transferred from an acid to a base in a Brønsted-Lowry acid-base reaction?
Key term
What is the pH of a solution with a hydrogen ion concentration of 1.0 × 10⁻³ mol dm⁻³?
Key term
What is the ionic product of water?
Key term
Write the general equilibrium expression for the dissociation of a weak acid HA in water.
Key term
What is the typical shape of a pH curve for the titration of a strong acid with a weak base?
Key term
What determines whether an indicator is suitable for a particular acid-base titration?
Key term
What two components make up a basic buffer solution?
Take Acids and Bases further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Brønsted–Lowry acid vs Brønsted–Lowry base
Brønsted–Lowry acid: a species donating a proton. Brønsted–Lowry base: a species accepting a proton.
Strong acid vs Weak acid
Strong acid: a proton donor that fully dissociates in water. Weak acid: a proton donor that only partially dissociates in water.
Equivalence point vs End point
Equivalence point: stage where reactants have combined in the exact stoichiometric ratio. End point: stage where an indicator changes colour.
Questions from this topic
Each one with the model answer underneath.
- 1
According to the Brønsted-Lowry theory, what is an acid?
Model answer
A proton donor
- 2
According to the Brønsted-Lowry theory, what is a base?
Model answer
A proton acceptor
- 3
What particle is transferred from an acid to a base in a Brønsted-Lowry acid-base reaction?
Model answer
A proton (H⁺)
- 4
In the reaction between HCl and NH₃, identify the Brønsted-Lowry acid.
Model answer
HCl
- 5
In the reaction between HCl and NH₃, identify the Brønsted-Lowry base.
Model answer
NH₃
- 6
What is a conjugate acid?
Model answer
The species formed when a base accepts a proton
What is inside Levo
Six ways to work the same material.
Acids and Bases revision questions
- What does Acids and Bases cover in AQA A-Level Chemistry?
- 7 subtopics: brønsted-lowry acid-base equilibria, the ph scale and strong acids, the ionic product of water and strong bases, weak acids and ka, ph curves and acid-base titrations, indicators and buffer solutions. Each one has its own page with questions and model answers.
- How is Acids and Bases organised?
- By the AQA 7405 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Acids and Bases, 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.
Or £46 a year, about £3.83 a month. Cancel anytime.