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
Specified Practical Work
- 9 subtopics
- 27 things to know
- Component 3
What Specified Practical Work covers
Specified Practical Work is examined in all three components: alongside the topics it belongs to on Components 1 and 2, and with extra weight on Component 3, Chemistry in Practice. It covers gravimetric analysis and qualitative analysis of unknown solutions, standard solutions, standardising an acid and preparing a soluble salt, back titration and double titration, determining enthalpy changes by calorimetry, following a rate by gas collection, the iodine clock and reaction order, electrochemical cells, redox titration and the estimation of copper, determining an equilibrium constant and following a titration with a pH probe, hydrolysis of 1-bromobutane and the preparation of an ester and organic synthesis, purification and identification.
Where it is assessed
Component 3
the practical examination, and drawn on throughout Components 1 and 2.
Check the Eduqas specification ↗The 9 subtopics
Each one has its own page.
- Gravimetric analysis and qualitative analysis of unknown solutionsRecall questions on the gravimetric method from precipitation through filtration and washing to heating to constant mass, why constant mass matters, the calculation from the mass of precipitate, and the systematic qualitative testing of an unknown solution for its cation and anion.Open →
- Standard solutions, standardising an acid and preparing a soluble saltRecall questions on preparing a standard solution in a volumetric flask, why a primary standard must be pure and stable, standardising an acid against it, preparing a soluble salt by titration and then without the indicator, and the calculations at each stage.Open →
- Back titration and double titrationRecall questions on when a back titration is used in preference to a direct one, the method and the calculation by difference, why the reagent must be in genuine excess, the double titration with two indicators, and worked purity determinations.Open →
- Determining enthalpy changes by calorimetryRecall questions on the apparatus and procedure, the excess-reagent and matched-solution requirements of an indirect determination, applying q = mcΔT, extrapolating the temperature back to mixing, the main sources of error, and worked determinations checked against the accepted value.Open →
- Following a rate by gas collection, the iodine clock and reaction orderRecall questions on the gas syringe method and what is plotted, why one over the time to a fixed stage measures the initial rate in a clock reaction, the chemistry of the iodine clock, determining an order from a series of runs, and the variables that must be controlled.Open →
- Electrochemical cells, redox titration and the estimation of copperStandard conditions under which electrode potentials are compared and why dilute sulfuric acid.Open →
- Determining an equilibrium constant and following a titration with a pH probeRecall questions on the esterification equilibrium determination and its calculation, why the mixture is left to reach equilibrium and then titrated cold, calibrating and using a pH probe, what a pH curve shows that an indicator cannot, and locating the equivalence point from the curve.Open →
- Hydrolysis of 1-bromobutane and the preparation of an esterRecall questions on the reflux apparatus and the reagents for the hydrolysis, the co-solvent problem and why ethanol is added, the preparation of an ester and its separation by distillation, the washing and drying steps, and the yield calculation.Open →
- Organic synthesis, purification and identificationRecall questions on the sequence from reaction through separation and purification to identification, recrystallising a solid and distilling a liquid, confirming purity by melting temperature or boiling range, identifying the product spectroscopically, and calculating the percentage yield.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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Describe how 250 cm³ of a standard solution is prepared from a weighed solid.
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Explain why anhydrous sodium carbonate can be used as a primary standard but solid sodium hydroxide cannot.
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Outline how a pure sample of a soluble salt is prepared by titration.
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What effect does a sodium hydroxide solution having stood open to the air have on the result of a double titration?
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Describe how a temperature against time graph is used to correct a calorimetry result for heat loss.
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Explain why the enthalpy change for magnesium oxide reacting with carbon dioxide is found indirectly rather than by direct measurement.
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Why is an experimental enthalpy change of combustion always less exothermic than the accepted value?
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In a gas collection rate experiment, what is plotted on each axis and what does the shape of the curve show?
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Describe how an iodine clock reaction is used to measure a rate.
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How is a salt bridge made, and why is potassium nitrate usually chosen for it?
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Why is starch added only when the iodine colour has faded to pale straw rather than at the start of a thiosulfate titration?
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Describe how a titration curve is obtained using a pH probe on a data logger.
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Describe how the relative rates of hydrolysis of 1-chlorobutane, 1-bromobutane and 1-iodobutane are compared experimentally.
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State in order the operations that convert a crude solid organic product into a pure dry sample.
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Describe two-way paper chromatography and explain what it achieves.
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What is the underlying principle of a gravimetric analysis by precipitation?
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Why is the percentage of calcium carbonate in limestone found by a back titration rather than by titrating the solid directly?
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When an equilibrium constant for esterification is determined, why is the sealed mixture left for about a week before it is titrated?
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Why is ethanol added to the mixture when 1-bromobutane is hydrolysed by aqueous sodium hydroxide?
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Why is the precipitating reagent added in excess in a gravimetric determination?
Process
Outline the procedure for determining the percentage of calcium carbonate in limestone by back titration.
Key term
What does the gradient of the tangent to a gas volume against time curve at the origin represent?
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Describe how an electrochemical cell is assembled to measure a cell potential.
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When an esterification equilibrium is studied, why must the reaction bottle be tightly stoppered?
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Why must the top of a reflux condenser be left open to the atmosphere?
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What does the melting temperature of the final product tell a chemist at the end of a synthesis?
Take Specified Practical Work further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
What is the underlying principle of a gravimetric analysis by precipitation?
Model answer
The species being measured is converted quantitatively into an insoluble compound of known formula, which is then filtered off, dried and weighed, so the mass of solid gives the amount of the original species.
- 2
Why is the precipitating reagent added in excess in a gravimetric determination?
Model answer
Excess reagent makes certain that every ion of the species being measured is thrown out of solution, so none is left behind to make the weighed mass too low.
- 3
Why is the precipitate washed with distilled water before it is dried?
Model answer
Soluble ions from the excess reagent and from the spectator ions cling to the surface of the solid, and washing removes them so that only the precipitate itself is weighed.
- 4
Explain what drying to constant mass means and why it is done.
Model answer
The solid is heated, cooled and weighed repeatedly until two successive masses agree, which shows that all the water has been driven off and the mass being recorded is that of the dry precipitate alone.
- 5
Why is the crucible cooled in a desiccator rather than on the bench?
Model answer
A desiccator keeps the cooling solid out of contact with atmospheric moisture, which would otherwise be reabsorbed and give a mass that creeps upwards while it is being weighed.
- 6
What effect does a small amount of precipitate passing through the filter paper have on the calculated result?
Model answer
The weighed mass is smaller than it should be, so the calculated amount and concentration of the original species both come out too low.
What is inside Levo
Six ways to work the same material.
Specified Practical Work revision questions
- What does Specified Practical Work cover in Eduqas A-Level Chemistry?
- 9 subtopics: gravimetric analysis and qualitative analysis of unknown solutions, standard solutions, standardising an acid and preparing a soluble salt, back titration and double titration, determining enthalpy changes by calorimetry, following a rate by gas collection, the iodine clock and reaction order, electrochemical cells, redox titration and the estimation of copper, determining an equilibrium constant and following a titration with a ph probe, hydrolysis of 1-bromobutane and the preparation of an ester and organic synthesis, purification and identification. Each one has its own page with questions and model answers.
- How is Specified Practical Work organised?
- By the Eduqas A410QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Specified Practical Work, 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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