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
Entropy and Feasibility of Reactions
- 5 subtopics
- 15 things to know
- Component 1
What Entropy and Feasibility of Reactions covers
Entropy and Feasibility of Reactions is examined in Component 1, Physical and Inorganic Chemistry, and drawn on again in Component 3. It covers entropy as a measure of freedom, entropy of solids, liquids and gases, Calculating entropy changes from absolute entropies, Gibbs free energy change and feasibility, spontaneity and endothermic processes.
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.
- Entropy as a measure of freedomRecall questions on what entropy measures, its symbol and units, what value an ordered system has, the entropy change when a solid dissolves, melts or boils, why a gas has a far higher entropy than a solid, and predicting the sign of an entropy change from an equation.Open →
- Entropy of solids, liquids and gasesRecall questions on the order of entropy across the three states and the reason for it, the large jump on boiling compared with melting, the entropy change when the number of moles of gas changes in a reaction, and worked predictions of the sign for named reactions.Open →
- Calculating entropy changes from absolute entropiesRelationship used to calculate an entropy change from absolute entropies, units of an entropy change calculated for a reaction and why a reaction with a positive entropy change is favoured.Open →
- Gibbs free energy changeEquation that defines the Gibbs free energy change and units of each quantity used in the Gibbs equation.Open →
- Feasibility, spontaneity and endothermic processesSpontaneous reaction in terms of Gibbs free energy, how an endothermic reaction can be spontaneous and spontaneous endothermic process.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
For which signs of ΔH and ΔS is a reaction feasible at all temperatures, at none, or only at high temperatures?
Key term
Place the solid, liquid and gaseous states in order of increasing entropy.
Numbers
State the relationship used to calculate an entropy change from absolute entropies.
Key term
Explain how an endothermic reaction can be spontaneous.
Key term
Give the symbol and the units of entropy.
Key term
Which has the greater entropy, one mole of steam at 100 °C or one mole of liquid water at 100 °C?
Key term
Why must each absolute entropy be multiplied by a number before the totals are found?
Key term
State the equation that defines the Gibbs free energy change.
Process
Give an example of a spontaneous endothermic process.
Key term
What kind of entropy value does a highly ordered system have?
Key term
Which has the greater entropy, one mole of ice or one mole of liquid water at 0 °C?
Key term
State the units of an entropy change calculated for a reaction.
Key term
State the units of each quantity used in the Gibbs equation.
Numbers
Calculate ΔG at 298 K for the dissolving of ammonium chloride, given ΔH = +15 kJ mol⁻¹ and ΔS = +75 J K⁻¹ mol⁻¹.
Take Entropy and Feasibility of Reactions further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
What does the entropy of a system measure?
Model answer
It measures the freedom possessed by the particles within the system, and so how disordered the system is.
- 2
Give the symbol and the units of entropy.
Model answer
The symbol is S and the units are J K⁻¹ mol⁻¹.
- 3
What happens to the total entropy of the universe in any natural change?
Model answer
It increases, moving towards a maximum.
- 4
What is meant by a natural or spontaneous change?
Model answer
It is a change that proceeds of its own accord once started, without needing a continuous supply of energy from outside.
- 5
What kind of entropy value does a highly ordered system have?
Model answer
A low one, because its particles have very little freedom.
- 6
Describe and explain the change in entropy when an ionic solid dissolves in water.
Model answer
The entropy increases, because the ordered lattice is broken up and the ions become free to move throughout the solution.
What is inside Levo
Six ways to work the same material.
Entropy and Feasibility of Reactions revision questions
- What does Entropy and Feasibility of Reactions cover in Eduqas A-Level Chemistry?
- 5 subtopics: entropy as a measure of freedom, entropy of solids, liquids and gases, calculating entropy changes from absolute entropies, gibbs free energy change and feasibility, spontaneity and endothermic processes. Each one has its own page with questions and model answers.
- How is Entropy and Feasibility of Reactions organised?
- By the Eduqas A410QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Entropy and Feasibility of 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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