Key term
Eduqas A-Level Chemistry A410QS
Formulae and Equations
Basic Ideas About Atoms
Topic overviewRadioactive decay and nuclear equationsBehaviour of α, β and γ radiationHalf-life and radioactive decay calculationsRadiation hazards and the uses of radioisotopesIonisation energy and its variation between elementsSuccessive ionisation energies and electronic structureOrbitals and electron configurations of elements 1 to 36Emission and absorption spectraThe hydrogen spectrum, E = hf and the convergence limit
Chemical Calculations
Topic overviewRelative atomic, isotopic, formula and molecular massPrinciples of the mass spectrometerMass spectra, isotopic abundance and relative atomic massEmpirical and molecular formulaeThe mole, the Avogadro constant and molar massMoles, grams and numbers of particlesConcentration and solubilityMolar volume and gas volume correctionsThe ideal gas equationStoichiometry and reacting quantitiesAcid-base titration calculationsAtom economy, percentage yield and percentage error
Bonding
Solid Structures
The Periodic Table
Topic overviewArrangement of the elements and the s-, p- and d-blocksOxidation and reduction as electron transferTrends across periods and down groupsReactions of Group 2 elements with oxygen, water and steamReactions of the aqueous cations Mg²⁺, Ca²⁺ and Ba²⁺Flame coloursReactivity of Group 1 and Group 2 metalsThermal stability of the Group 2 carbonates and hydroxidesSolubility of the Group 2 hydroxides and sulfatesBasic character of the Group 1 and Group 2 oxides and hydroxidesVolatility of the halogens and their reactions with metalsOxidising power, displacement reactions and the silver nitrate testWater treatment, salt preparation and gravimetric analysis
Simple Equilibria and Acid-Base Reactions
Thermochemistry
Rates of Reaction
The Wider Impact of Chemistry
Organic Compounds
Hydrocarbons
Topic overviewAlkanes and the sigma-bonded frameworkCombustion of alkanes and the use of fossil fuelsFree radical substitution and the photochlorination of alkanesAlkenes and the reactivity of the C=C bondE–Z isomerismElectrophilic addition of bromine to alkenesTests for alkenesMarkovnikov addition of hydrogen bromide and carbocation stabilityCatalytic hydrogenation of alkenesAddition polymerisation
Halogenoalkanes
Topic overviewNucleophilic substitution of primary halogenoalkanesElimination reactions forming alkenesBond polarity, bond enthalpy and the ease of substitutionThe silver nitrate test for halogenoalkanesUses of halogenoalkanes and the regulation of their useCFCs and their effect in the upper atmosphereHeating under reflux
Alcohols and Carboxylic Acids
Topic overviewIndustrial preparation of ethanol from etheneFermentation and the distillation of ethanolBiofuels and the issues they raiseClassifying alcohols as primary, secondary and tertiaryDehydration of alcohols to alkenesOxidation of primary alcohols to aldehydes and carboxylic acidsOxidation of secondary alcohols to ketonesThe dichromate(VI) test for alcoholsCarboxylic acids and the sodium hydrogencarbonate testReactions of carboxylic acids with bases, carbonates and hydrogencarbonatesEsterification and separation by distillation
Instrumental Analysis
Redox and Standard Electrode Potential
Redox Reactions
Chemistry of the P-Block
Topic overviewAmphoteric behaviour of aluminium and leadThe inert pair effect in Groups 3, 4 and 5Electron-deficient compounds and expanded octetsAl₂Cl₆ and donor-acceptor compoundsHexagonal and cubic boron nitrideStability of oxidation states II and IV in Group 4Carbon dioxide and lead(II) oxideBonding in the Group 4 chloridesHydrolysis of the Group 4 chloridesReactions of aqueous lead(II) ionsChlorine with cold and warm aqueous sodium hydroxideBleaching and bactericidal action of chlorine and chlorate(I)Sodium halides with concentrated sulfuric acid
Chemistry of the D-Block Transition Metals
Topic overviewOxidation states of the d-block elementsImportant oxidation states and the colours of aqueous ionsBonding in tetrahedral and octahedral complexesThe origin of colour and the splitting of d-orbitalsLigand exchange and change of coordination numberColours and formulae of copper and cobalt complex ionsHeterogeneous and homogeneous catalysisNickel in hydrogenation and iron in the Haber processVanadium(V) oxide and manganese(IV) oxide as catalystsReactions of Cr³⁺, Fe²⁺, Fe³⁺ and Cu²⁺ with excess aqueous hydroxide
Chemical Kinetics
Enthalpy Changes for Solids and Solutions
Entropy and Feasibility of Reactions
Equilibrium Constants
Acid-Base Equilibria
Topic overviewThe Lowry–Brønsted theory and conjugate pairsStrong and weak acids and the dissociation constant KaThe ionic product of water, KwpH of strong acids and strong basespH of weak acids from Ka and pKaTitration curvesHow buffer solutions workBuffer calculationsBuffers in living systems and industrySalt hydrolysis and the choice of indicator
Stereoisomerism
Aromaticity
Alcohols and Phenols
Aldehydes and Ketones
Topic overviewPreparing aldehydes and ketones by oxidation of alcoholsDistinguishing aldehydes and ketones with Tollens’ reagent and Fehling’s solutionReduction of aldehydes and ketones using NaBH₄Nucleophilic addition of HCN to aldehydes and ketonesReaction with 2,4-dinitrophenylhydrazineThe triiodomethane (iodoform) test
Carboxylic Acids and Their Derivatives
Topic overviewRelative acidity of carboxylic acids, phenols, alcohols and waterPreparing carboxylic acids by oxidationReduction and decarboxylation of carboxylic acidsAcid chlorides and their reactionsEsters and their hydrolysisAmides and their hydrolysisNitriles from carboxylic acids and halogenoalkanesHydroxynitriles, hydrolysis and reduction of nitriles
Amines
Amino Acids, Peptides and Proteins
Organic Synthesis and Analysis
Topic overviewPlanning a multi-step synthesisChoosing between alternative routesManipulation and separation techniquesPurification and melting temperatureAddition and condensation polymerisationPolyesters and polyamidesHigh resolution proton NMRCombining spectra to elucidate a structureInterpreting chromatographic dataGas chromatography and HPLC
Specified Practical Work
Topic overviewGravimetric analysis and qualitative analysis of unknown solutionsStandard solutions, standardising an acid and preparing a soluble saltBack titration and double titrationDetermining enthalpy changes by calorimetryFollowing a rate by gas collection, the iodine clock and reaction orderElectrochemical cells, redox titration and the estimation of copperDetermining an equilibrium constant and following a titration with a pH probeHydrolysis of 1-bromobutane and the preparation of an esterOrganic synthesis, purification and identification
Practical Skills and Techniques
Topic overviewChoosing apparatus and recording measurementsVolumetric technique with pipette, burette and volumetric flaskTitration procedure and the choice of indicatorHeating, heating under reflux and distillationFiltration, purification and qualitative testingMelting temperature, chromatography and electrochemical cellsVariables, errors and risk in evaluating a method
Mathematical Skills in Chemistry
Topic overviewStandard form, units and significant figuresRatios, fractions and percentagesChanging the subject and substituting valuesLogarithms, pH and pKaExponentials, the Arrhenius equation and rateGraphs, gradients and interceptsTangents and rates of changeArea under a curveUncertainty and combining errorsThe gas equation and equilibrium expressions
Simple Equilibria and Acid-Base Reactions
- 6 subtopics
- 18 things to know
- Components 1 and 2
What Simple Equilibria and Acid-Base Reactions covers
Simple Equilibria and Acid-Base Reactions is examined in Components 1 and 2, since the Core Ideas are examined on both written papers, and drawn on again in Component 3. It covers reversible reactions and dynamic equilibrium, Le Chatelier's principle, the equilibrium constant Kc, acids and bases as donors and acceptors of H⁺, strong and weak acids, pH and hydrogen ion concentration and acid-base titrations.
Where it is assessed
Components 1 and 2
the Core Ideas, Principles and Concepts, which are examined on both written papers and drawn on again in Component 3.
Check the Eduqas specification ↗The 6 subtopics
Each one has its own page.
- Reversible reactions and dynamic equilibriumRecall questions on what makes a reaction reversible and the meaning of the double half-arrow, the conditions for a dynamic equilibrium, why the concentrations stay constant while both reactions continue, why a closed system is required, and how equilibrium can be approached from either side.Open →
- Le Chatelier's principleRecall questions on the statement of the principle, the effect of changing concentration, pressure and temperature on the position of equilibrium, why a catalyst changes nothing, and the compromise conditions chosen for a named industrial process.Open →
- The equilibrium constant KcRecall questions on writing a Kc expression from a balanced equation, deducing its units by cancelling, substituting given equilibrium concentrations, what a large or small value indicates about the extent of reaction, and the one condition that changes the value.Open →
- Acids and bases as donors and acceptors of H⁺Acid in terms of hydrogen ions, base in terms of hydrogen ions and diprotic acid.Open →
- Strong and weak acids, pH and hydrogen ion concentrationRecall questions on the difference between a strong and a weak acid and between strength and concentration, the definition of pH, calculating pH from the hydrogen ion concentration and back again, the pH of a strong acid of stated concentration, and why a weak acid of the same concentration has a higher pH.Open →
- Acid-base titrationsAcid-base titration used to find, standard solution and end point of a titration.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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Explain how a double titration allows a mixture of sodium hydroxide and sodium carbonate to be analysed.
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What is meant by a reversible reaction?
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State Le Chatelier's principle.
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Write the expression for Kc for the equilibrium N₂(g) + 3H₂(g) ⇌ 2NH₃(g).
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Define an acid in terms of hydrogen ions.
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Explain the difference between a strong acid and a weak acid.
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State the two conditions that must hold for a chemical system to be at dynamic equilibrium.
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The oxidation 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) is exothermic. Predict and explain the effect of raising the temperature on the yield of sulfur trioxide.
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Deduce the units of Kc for the equilibrium N₂(g) + 3H₂(g) ⇌ 2NH₃(g).
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Define a base in terms of hydrogen ions.
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Write the equation for the dissociation of ethanoic acid in water.
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Explain why a reversible reaction carried out in an open beaker may never reach equilibrium.
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What happens to the position of the equilibrium CH₃COOH + C₂H₅OH ⇌ CH₃COOC₂H₅ + H₂O when extra ethanol is added?
Numbers
Calculate Kc for N₂O₄(g) ⇌ 2NO₂(g) in a mixture where [N₂O₄] = 0.050 mol dm⁻³ and [NO₂] = 0.020 mol dm⁻³.
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What is an alkali?
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Why is an equilibrium arrow used for ethanoic acid but a single arrow for hydrochloric acid?
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What is a standard solution?
Take Simple Equilibria and Acid-Base Reactions further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by a reversible reaction?
Model answer
A reversible reaction is one in which the products can react together to re-form the reactants, so the change can run in both directions under the same conditions.
- 2
State the two conditions that must hold for a chemical system to be at dynamic equilibrium.
Model answer
The forward and reverse reactions must be proceeding at equal rates, and the system must be closed so that nothing can enter or leave.
- 3
Why is chemical equilibrium described as dynamic rather than static?
Model answer
Both reactions carry on at the molecular level even though nothing appears to change, because the two rates are equal rather than zero.
- 4
What happens to the concentrations of reactants and products once equilibrium has been established?
Model answer
They remain constant, although they are not usually equal to one another.
- 5
Explain why a reversible reaction carried out in an open beaker may never reach equilibrium.
Model answer
A gaseous product can escape from an open vessel, so the reverse reaction can never keep pace and the forward change continues until the reactants are used up.
- 6
What symbol is written in an equation to show that a reaction is reversible?
Model answer
The double half-arrow ⇌ is used.
What is inside Levo
Six ways to work the same material.
Simple Equilibria and Acid-Base Reactions revision questions
- What does Simple Equilibria and Acid-Base Reactions cover in Eduqas A-Level Chemistry?
- 6 subtopics: reversible reactions and dynamic equilibrium, le chatelier's principle, the equilibrium constant kc, acids and bases as donors and acceptors of h⁺, strong and weak acids, ph and hydrogen ion concentration and acid-base titrations. Each one has its own page with questions and model answers.
- How is Simple Equilibria and Acid-Base Reactions organised?
- By the Eduqas A410QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Simple Equilibria and Acid-Base Reactions, 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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