Process
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
Redox Reactions
- 5 subtopics
- 15 things to know
- Component 1
What Redox Reactions covers
Redox Reactions is examined in Component 1, Physical and Inorganic Chemistry, and drawn on again in Component 3. It covers Constructing ion/electron half-equations, combining half-equations into a stoichiometric redox equation, the reaction of Cu²⁺ with iodide ions, carrying out a redox titration and redox titration calculations.
Where it is assessed
Component 1
Physical and Inorganic Chemistry, and drawn on again in Component 3.
Check the Eduqas specification ↗The 5 subtopics
Each one has its own page.
- Constructing ion/electron half-equationsRecall questions on the sequence for balancing a half-equation in acid solution, balancing the atoms then the oxygens with water, the hydrogens with hydrogen ions and the charge with electrons, and worked half-equations for the common oxidising and reducing agents.Open →
- Combining half-equations into a stoichiometric redox equationMole ratio in which manganate(VII) ions react with iron(II) ions, mole ratio in which dichromate(VI) ions react with iron(II) ions and mole ratio in which iodine reacts with thiosulfate ions.Open →
- The reaction of Cu²⁺ with iodide ionsRecall questions on the equation and the observations, why copper(II) is reduced to copper(I) iodide, the iodine released and the starch test for it, why the mixture is titrated against thiosulfate, and the calculation of the copper content from the titre.Open →
- Carrying out a redox titrationWhy ethanoic acid is unsuitable for acidifying a manganate(VII) titration, purpose of a rough titration and concordant titres.Open →
- Redox titration calculationsRecall questions on the manganate(VII) and dichromate(VI) half-equations, combining them with the reducing agent to give the reaction ratio, the mole calculation from the titre, expressing the result as a concentration or a percentage purity, and checking the answer against the titre.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
Calculate the amount of iron(II) ions oxidised by 25.0 cm³ of 0.100 mol dm⁻³ potassium dichromate(VI).
Key term
What must be done to two half-equations before they can be added together?
Key term
Write the equation for the reaction between copper(II) ions and an excess of iodide ions.
Key term
Explain why hydrochloric acid must not be used to acidify a manganate(VII) titration.
Key term
Write the half-equation for the reduction of acidified dichromate(VI) ions to chromium(III) ions.
Key term
Give the overall equation for the reaction between acidified manganate(VII) ions and iron(II) ions.
Key term
Which species is reduced when copper(II) ions react with iodide ions?
Key term
Explain why nitric acid must not be used to acidify a manganate(VII) titration.
Numbers
A 25.0 cm³ portion of an iron(II) solution needs 22.5 cm³ of 0.0200 mol dm⁻³ potassium manganate(VII). Calculate the concentration of the iron(II) solution.
Numbers
How many electrons are gained per dichromate(VI) ion, and what oxidation number change causes this?
Key term
State the mole ratio in which manganate(VII) ions react with iron(II) ions.
Key term
Which species is oxidised when copper(II) ions react with iodide ions?
Key term
Why is the burette reading for potassium manganate(VII) taken at the top of the liquid surface?
Numbers
Calculate the volume of 0.0200 mol dm⁻³ potassium manganate(VII) needed to react with 20.0 cm³ of 0.0250 mol dm⁻³ sodium ethanedioate.
Take Redox Reactions further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
State the order of steps used to build a half-equation for a reaction in acidic solution.
Model answer
Balance the atoms other than oxygen and hydrogen, add water molecules to balance the oxygen, add H⁺ ions to balance the hydrogen, then add electrons to balance the charge.
- 2
Write the half-equation for the reduction of acidified dichromate(VI) ions to chromium(III) ions.
Model answer
Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O.
- 3
How many electrons are gained per dichromate(VI) ion, and what oxidation number change causes this?
Model answer
Six electrons are gained, because each of the two chromium atoms falls from +6 to +3.
- 4
Write the half-equation for the reduction of acidified manganate(VII) ions to manganese(II) ions.
Model answer
MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O.
- 5
State the change in oxidation number of manganese when manganate(VII) is reduced to manganese(II).
Model answer
Manganese falls from +7 to +2, a gain of five electrons.
- 6
Write the half-equation for the oxidation of thiosulfate ions to tetrathionate ions.
Model answer
2S₂O₃²⁻ → S₄O₆²⁻ + 2e⁻.
What is inside Levo
Six ways to work the same material.
Redox Reactions revision questions
- What does Redox Reactions cover in Eduqas A-Level Chemistry?
- 5 subtopics: constructing ion/electron half-equations, combining half-equations into a stoichiometric redox equation, the reaction of cu²⁺ with iodide ions, carrying out a redox titration and redox titration calculations. Each one has its own page with questions and model answers.
- How is Redox Reactions organised?
- By the Eduqas A410QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Redox 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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