OCR AS Level in Chemistry A (H032) - BioChem Tuition · PDF fileOCR AS Level in Chemistry A (H032) ... How To Achieve Grade ‘A’ ... science courses at GCSE level. This module provides

Dr. Faisal Rana www.biochemtuition.com

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OCR AS Level in Chemistry A (H032)

Breadth in Chemistry (01)

& Depth in

Chemistry (02)

OCR AS Level in Chemistry A

Module 1

Development of practical skills in

chemistry

Dr. Faisal Rana www.biochemtuition.com Mobile: 07783919244

[email protected]

Module 2

Foundations in chemistry

Module 3

Periodic table and energy

Module 4

Core organic chemistry


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OCR AS Level in Chemistry A (H032) – Breadth in Chemistry H032/01

1. Exam paper- Breadth in Chemistry H032/01 1 hour 30 min written paper

50 % of AS Chemistry

Overview of teaching modules

Module 1: Development of practical skills in chemistry

• Practical skills assessed in a written examination.

Module 2: Foundations in chemistry

• Atoms, compounds, molecules and equations. • Amount of substance. • Acid-base and redox reactions. • Electrons, bonding and structure.

Module 3: Periodic table and energy

• The periodic table and periodicity

• Group 2 and the halogens

• Qualitative analysis

• Enthalpy changes

• Reactions rates and equilibrium (qualitative)

Module 4: Core Organic Chemistry

• Basic concepts

• Hydrocarbons

• Alcohols and haloalkanes

• Organic synthesis

• Analytical techniques (IR and MS)

Overview of assessment

• The unit is assessed through a 1-hour & 30 min examination paper set and marked by OCR.

• The total number of marks is 70.

• Grades A–E are available.


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OCR AS Level in Chemistry A (H032) – Depth in chemistry H032/02

2. Exam paper- Depth in chemistry H032/01 1 hour 30 min written paper

50 % of AS Chemistry

Overview of teaching modules

Module 1: Development of practical skills in chemistry

• Practical skills assessed in a written examination.

Module 2: Foundations in chemistry

• Atoms, compounds, molecules and equations. • Amount of substance. • Acid-base and redox reactions. • Electrons, bonding and structure.

Module 3: Periodic table and energy

• The periodic table and periodicity

• Group 2 and the halogens

• Qualitative analysis

• Enthalpy changes

• Reactions rates and equilibrium (qualitative)

Module 4: Core Organic Chemistry

• Basic concepts

• Hydrocarbons

• Alcohols and haloalkanes

• Organic synthesis

• Analytical techniques (IR and MS)

Overview of assessment

• The unit is assessed through a 1-hour & 30 min examination paper set and marked by OCR.

• The total number of marks is 70.

• Grades A–E are available.


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Intensive tutoring

1. Complete Revision of Modules 1-4 2. Practice topic by topic examination style questions on Modules 1-4.

Strategies for Attacking BMAT Section 1

1. Solve mock examination papers to prepare for the exam

Mock examination practice Past papers practice (2001-‐2014)

How To Achieve Grade ‘A’ Breadth in chemistry & Depth in chemistry

1. Solve relevant questions from past papers. We have dedicated question

packs targeting MCQs, Short answer questions and extended

answer questions. 2. Revisit the mistakes/revise topics.

- Critical Reasoning Skills

Three-‐pronged strategy to grade A or A*

OCR AS Chemistry Specification H032 Modules 1 to 4

© OCR 2014AS Level in Chemistry A 7

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2c. Contentofmodules1to4

Module1:Developmentofpracticalskillsinchemistry

Chemistryisapracticalsubjectandthedevelopmentofpracticalskillsisfundamentaltounderstandingthe nature of chemistry. Chemistry A gives learners manyopportunitiestodevelopthefundamentalskills

needed to collect and analyse empirical data. Skills in planning,implementing,analysingandevaluating,asoutlinedin1.1,willbeassessedinthewrittenpapers.

1.1Practicalskillsassessedinawrittenexamination

Practicalskillsareembeddedthroughoutallmodulesinthisspecification.

Learners will be required to develop a range of practicalskillsthroughoutthecourseinpreparationforthewrittenexaminations.

1.1.1Planning

Learningoutcomes Additionalguidance

Learners should be able to demonstrate and apply their knowledge and understanding of:

(a) experimental design, including to solve problems setinapracticalcontext

Includingselectionofsuitableapparatus,equipmentand techniques for the proposed experiment.

Learnersshouldbeabletoapplyscientificknowledgebasedonthecontentofthespecificationtothepracticalcontext. HSW3

(b) identificationofvariablesthatmustbecontrolled, where appropriate

(c) evaluationthatanexperimentalmethodisappropriate to meet the expected outcomes.

HSW6

1.1.2Implementing



(a) howtouseawiderangeofpracticalapparatusand techniques correctly

Asoutlinedinthecontentofthespecification. HSW4

(b) appropriate units for measurements M0.0

(c) presentingobservationsanddatainanappropriate format.

HSW8

© OCR 2014AS Level in Chemistry A8

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1.1.3 Analysis



(a) processing,analysingandinterpretingqualitativeandquantitativeexperimentalresults

Including reaching valid conclusions, where appropriate. HSW5

(b) useofappropriatemathematicalskillsforanalysisofquantitativedata

RefertoSection5foralistofmathematicalskillsthat learners should have acquired competence in as part of the course. HSW3

(c) appropriateuseofsignificantfigures M1.1

(d) plottingandinterpretingsuitablegraphsfromexperimental results, including:(i) selectionandlabellingofaxeswith

appropriatescales,quantitiesandunits(ii) measurement of gradients.

M3.2

M3.3, M3.4, M3.5

1.1.4Evaluation



(a) how to evaluate results and draw conclusions HSW6

(b) theidentificationofanomaliesinexperimentalmeasurements

(c) thelimitationsinexperimentalprocedures

(d) precision and accuracy of measurements and data, including margins of error, percentage errorsanduncertaintiesinapparatus

M1.3

(e) refiningexperimentaldesignbysuggestionofimprovements to the procedures and apparatus.

HSW3


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Module2:Foundationsinchemistry

This module acts as an important bridge into AS and A Level Chemistry from the study of chemistry within science courses at GCSE level.

This module provides learners with a knowledge and understanding of the important chemical ideas that underpin the study of AS Chemistry:

• atomic structure

• quantitativechemistry:formulae,equations,amount of substance and the mole

• reactionsofacids

• oxidationnumberandredoxreactions

• bonding and structure.

The importance of these basic chemical concepts is seen as a prerequisite for all further chemistry modules, and it is recommended that this module shouldbestudiedfirstduringthiscourse.

This module allows learners to develop important quantitativetechniquesinvolvedinmeasuringmasses,gasandsolutionvolumes,includinguseofvolumetricapparatus.

Learnersarealsoabletodeveloptheirmathematicalskills during their study of amount of substance and whencarryingoutquantitativepracticalwork.

2.1Atomsandreactions

ThissectionbuildsdirectlyfromGCSEScience,startingwith basic atomic structure and isotopes.

Importantbasicchemicalskillsaredeveloped:writingchemicalformulae,constructingequationsandcalculatingchemicalquantitiesusingtheconceptofamount of substance.

The role of acids, bases and salts in chemistry is developedinthecontextofneutralisationreactions.

Finally,redoxreactionsarestudiedwithinthecontextofoxidationnumberandelectrontransfer.

2.1.1Atomicstructureandisotopes



Atomicstructureandisotopes

(a) isotopes as atoms of the same element with differentnumbersofneutronsanddifferentmasses

(b) atomic structure in terms of the numbers of protons, neutrons and electrons for atoms and ions, given the atomic number, mass number and any ionic charge

HSW1Differentmodelsforatomicstructurecanbeusedtoexplaindifferentphenomena,e.g.theBohrmodelexplainsperiodicproperties.

HSW7 The changing accepted models of atomic structureovertime.Theuseofevidencetoacceptorrejectparticularmodels.


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Relativemass

(c) explanationofthetermsrelative isotopic mass (mass compared with 1/12th mass of carbon-12) and relative atomic mass (weighted mean mass compared with 1/12th mass of carbon-12), based on the mass of a 12C atom, the standard for atomic masses

Definitionsrequired.

(d) use of mass spectrometry in:(i) thedeterminationofrelativeisotopic

massesandrelativeabundancesoftheisotope

(ii) calculationoftherelativeatomicmassofanelementfromtherelativeabundancesofitsisotopes

M0.2, M1.2, M3.1

Knowledge of the mass spectrometer not required. Limited to ions with single charges.

(e) use of the terms relative molecular mass, Mr , and relative formula massandtheircalculationfromrelativeatomicmasses.

For simple molecules, the term relative molecular mass will be used.

For compounds with giant structures, the term relative formula mass will be used.

Definitionsofrelativemolecularmassandrelativeformula mass will not be required.

2.1.2Compounds,formulaeandequations



Formulaeandequations

(a) thewritingofformulaeofioniccompoundsfromionic charges, including:(i) predictionofionicchargefromtheposition

of an element in the periodic table(ii) recall of the names and formulae for the

followingions:NO3–, CO3

2–, SO42–, OH–,

NH4+, Zn2+ and Ag+

Notethat‘nitrate’and‘sulfate’shouldbeassumedtobeNO3

– and SO42–.

Charges on ions other than in (i) and (ii) will be provided.

(b) constructionofbalancedchemicalequations(includingionicequations),includingstatesymbols,forreactionsstudiedandforunfamiliarreactionsgivenappropriateinformation.

M0.2


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2.1.3Amountofsubstance



The mole

(a) explanationanduseoftheterms:(i) amount of substance(ii) mole (symbol ‘mol’), as the unit for amount

of substance(iii) the Avogadro constant, NA (the number of

particlespermole,6.02×1023 mol–1)(iv) molar mass (mass per mole, units g mol–1)(v) molar gas volume (gas volume per mole,

units dm3 mol–1)

M0.0, M0.1, M0.2, M0.4

Amount of substance will be used in exams using theformulaofthesubstancee.g.amountofNaCl; amount of O2.

The value for NA and the molar gas volume at RTP are provided on the Data Sheet.

Determinationofformulae

(b) use of the terms:(i) empirical formula (the simplest whole

numberratioofatomsofeachelementpresent in a compound)

(ii) molecular formula (the number and type of atoms of each element in a molecule)

Definitions not required.

(c) calculationsofempiricalandmolecularformulae,fromcompositionbymassorpercentagecompositionsbymassandrelativemolecularmass

M0.2, M2.2, M2.3, M2.4

Toincludecalculatingempiricalformulaefromelemental analysis data.

(d) the terms anhydrous, hydrated and water of crystallisationandcalculationoftheformulaof a hydrated salt from given percentage composition,masscompositionorbasedonexperimental results

M0.2, M2.2, M2.3, M2.4

PAG1

Calculationofreactingmasses,gasvolumesandmoleconcentrations

(e) calculations,usingamountofsubstanceinmol,involving:(i) mass(ii) gas volume(iii) solutionvolumeandconcentration

M0.0, M0.1, M0.4, M1.1, M2.2, M2.3, M2.4

Learnerswillbeexpectedtoexpressconcentrationin mol dm–3 and g dm–3.

(f) theidealgasequation: pV = nRT

M0.0, M0.1, M0.4, M1.1, M2.2, M2.3, M2.4

The value for R is provided on the Data Sheet. Learnerswillbeexpectedtoexpressquantitiesin SI units.

(g) useofstoichiometricrelationshipsincalculations M0.2


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Percentageyieldsandatomeconomy

(h) calculationstodetermine:(i) thepercentageyieldofareactionorrelated

quantities(ii) theatomeconomyofareaction

M0.2, M1.1, M2.2, M2.3, M2.4

(i) the techniques and procedures required during experiments requiring the measurement of mass, volumesofsolutionsandgasvolumes

PAG1 HSW4Manyopportunitiestocarryoutexperimentalandinvestigativework.

(j) thebenefitsforsustainabilityofdevelopingchemical processes with a high atom economy.

HSW10 Use of processes with high atom economy in chemical industry and other areas.

2.1.4 Acids



Acids,bases,alkalisandneutralisation

(a) the formulae of the common acids (HCl, H2SO4, HNO3 and CH3COOH) and the common alkalis (NaOH,KOHandNH3)andexplanationthatacidsrelease H+ionsinaqueoussolutionandalkalisrelease OH–ionsinaqueoussolution

(b) qualitativeexplanationofstrongandweakacidsintermsofrelativedissociations

(c) neutralisationasthereactionof:(i) H+ and OH– to form H2O(ii) acids with bases, including carbonates,

metal oxides and alkalis (water-soluble bases),toformsalts,includingfullequations

Acid–basetitrations

(d) the techniques and procedures used when preparingastandardsolutionofrequiredconcentrationandcarryingoutacid–basetitrations


(e) structuredandnon-structuredtitrationcalculations,basedonexperimentalresultsoffamiliar and non-familiar acids and bases.

M0.1, M0.2, M1.1, M1.2, M2.2, M2.3, M2.4


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2.1.5 Redox



Oxidationnumber

(a) rulesforassigningandcalculatingoxidationnumber for atoms in elements, compounds and ions

Learnerswillbeexpectedtoknowoxidationnumbers of O in peroxides and H in metal hydrides.

(b) writingformulaeusingoxidationnumbers HSW8Appropriateuseofoxidationnumbersinwrittencommunication.

(c) use of a Roman numeral to indicate the magnitudeoftheoxidationnumberwhenan element may have compounds/ions with differentoxidationnumbers

Examples should include, but not be limited to, iron(II) and iron(III). Learners will be expected to write formulae from names such as chlorate(I) and chlorate(III) and vice versa. Notethat'nitrate’and‘sulfate’,withnoshownoxidationnumber,areassumedtobeNO3

– and SO4

2–.

HSW8Systematicandunambiguousnomenclature.

Redoxreactions

(d) oxidationandreductionintermsof:(i) electron transfer(ii) changesinoxidationnumber

Should include examples of s-, p- and d-block elements.

(e) redoxreactionsofmetalswithacidstoformsalts,includingfullequations(see also 2.1.4 c)

Metals should be from s-, p- and d- blocks e.g. Mg, Al, Fe, Zn. Ionicequationsnot required. In (e),reactionswithacidswillbelimitedtothoseproducingasaltandhydrogen.Reactionsinvolvingnitric acid or concentrated sulfuric acid could be assessed in the context of (f).

(f) interpretationofredoxequationsin(e), and unfamiliarredoxreactions,tomakepredictionsintermsofoxidationnumbersandelectronloss/gain.

M0.2


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2.2Electrons,bondingandstructure

Thissectionintroducestheconceptofatomicorbitalsand develops a deeper understanding of electron configurationslinkedtotheperiodictable.

The central role of electrons in ionic and covalent bonding is then studied. The important role of

moleculesisstudied,includinganexplanationofpolarityandintermolecularforces.Finally,thissectionlooks at how bonding and structure contribute to propertiesofsubstances.

2.2.1Electronstructure



Energylevels,shells,sub-shells, atomicorbitals,electronconfiguration

(a) thenumberofelectronsthatcanfillthefirstfourshells

(b) atomic orbitals, including: (i) as a region around the nucleus that can hold

up to two electrons, with opposite spins(ii) the shapes of s- and p-orbitals(iii) the number of orbitals making up s-, p- and

d-sub-shells, and the number of electrons thatcanfills-,p-andd-sub-shells

HSW1,7 Development of models to explain electron structure.

(c) fillingoforbitals:(i) forthefirstthreeshellsandthe4sand4p

orbitals in order of increasing energy(ii) for orbitals with the same energy,

occupationsinglybeforepairing

Learners are expected to be familiar with the 'electronsinbox'representations.

HSW1Developmentofrefinedmodelsforelectronstructure.

(d) deductionoftheelectronconfigurationsof:(i) atoms, given the atomic number, up to

Z=36(ii) ions, given the atomic number and ionic

charge, limited to s- and p-blocks up to Z=36.

Learnersshouldusesub-shellnotation,i.e.foroxygen: 1s22s22p4. TheelectronconfigurationsofCrandCuwillnot be assessed.


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2.2.2Bondingandstructure



Ionicbonding

(a) ionicbondingaselectrostaticattractionbetweenpositiveandnegativeions,andtheconstructionof'dot-and-cross'diagrams

(b) explanationofthesolidstructuresofgiantioniclattices,resultingfromoppositelychargedionsstronglyattractedinalldirectionse.g.NaCl

(c) explanationoftheeffectofstructureandbondingonthephysicalpropertiesofioniccompounds,includingmeltingandboilingpoints,solubilityandelectricalconductivityinsolid,liquid and aqueous states

HSW1 Use of ideas about ionic bonding to explain macroscopicproperties.

Covalentbonding

(d) covalentbondasthestrongelectrostaticattractionbetweenasharedpairofelectronsandthe nuclei of the bonded atoms

(e) constructionof‘dot-and-cross’ diagrams of molecules and ions to describe:(i) single covalent bonding(ii) multiplecovalentbonding(iii) dativecovalent(coordinate)bonding

‘Dot-and-cross’ diagrams of up to six electron pairs (including lone pairs) surrounding a central atom.

(f) use of the term average bond enthalpy as a measurement of covalent bond strength

Learners should appreciate that the larger the value of the average bond enthalpy, the stronger the covalent bond. Definitionandcalculationsnot required. Averagebondenthalpiesandrelatedcalculationsare covered in detail in 3.2.1 f.

Theshapesofsimplemoleculesandions

(g) the shapes of, and bond angles in, molecules and ions with up to six electron pairs (including lone pairs) surrounding the central atom as predicted byelectronpairrepulsion,includingtherelativerepulsive strengths of bonded pairs and lone pairs of electrons

M4.1, M4.2

Learners should be able to draw 3-D diagrams to illustrate shapes of molecules and ions.

HSW1,2 Using electron pair repulsion theory to predict molecular shapes.

(h) electron pair repulsion to explain the following shapes of molecules and ions: linear, non-linear, trigonal planar, pyramidal, tetrahedral and octahedral

Learners are expected to know that lone pairs repel more than bonded pairs and the bond angles for common examples of each shape including CH4(109.5°),NH3 (107°) and H2O (104.5°).


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Electronegativityandbondpolarity

(i) electronegativityastheabilityofanatomtoattractthebondingelectronsinacovalentbond;interpretationofPaulingelectronegativityvalues

Learnersshouldbeawarethatelectronegativityincreases towards F in the periodic table.

HSW1,2Usingideasaboutelectronegativitytopredict chemical bond type.

(j) explanationof:(i) a polar bond and permanent dipole within

molecules containing covalently-bonded atomswithdifferentelectronegativities

(ii) a polar molecule and overall dipole in terms of permanent dipole(s) and molecular shape

A polar molecule requires polar bonds with dipoles thatdonotcancelduetotheirdirectione.g.H2O and CO2 both have polar bonds but only H2O has an overall dipole.

Intermolecularforces

(k) intermolecular forces based on permanent dipole–dipoleinteractionsandinduced dipole–dipoleinteractions

Permanent dipole–dipole and induced dipole–dipole interactionscanboth be referred to as van der Waals’ forces.

Induceddipole–dipoleinteractionscanalsobereferred to as London (dispersion) forces.

HSW1,2Dipoleinteractionsasamodeltoexplainintermolecular bonding.

(l) hydrogen bonding as intermolecular bonding betweenmoleculescontainingN,OorFandtheHatomof–NH,–OHorHF

Including the role of lone pairs.

(m) explanationofanomalouspropertiesofH2O resultingfromhydrogenbonding,e.g.:(i) the density of ice compared with water(ii) itsrelativelyhighmeltingandboilingpoints

HSW1 Use of ideas about hydrogen bonding to explainmacroscopicproperties.

(n) explanationofthesolidstructuresofsimplemolecularlattices,ascovalentlybondedmoleculesattractedbyintermolecularforces,e.g. I2, ice

(o) explanationoftheeffectofstructureandbondingonthephysicalpropertiesofcovalentcompoundswithsimplemolecularlatticestructuresincludingmeltingandboilingpoints,solubilityandelectricalconductivity.


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Module3:Periodictableandenergy

The focus of this module is inorganic and physical chemistry,theapplicationsofenergyusetoeveryday life and industrial processes, and current environmental concerns associated with sustainability.

The content within this module assumes knowledge and understanding of the chemical concepts developed inModule2:Foundationsinchemistry.

This module provides learners with a knowledge and understanding of the important chemical ideas that underpin the study of inorganic and physical chemistry:

• theperiodictable:periodicandgroupproperties

• enthalpychangesandtheirdetermination

• ratesofreaction

• reversiblereactionsandchemicalequilibrium

• considerationofenergyandyieldinimprovingsustainability.

This module allows learners to develop important qualitativepracticalskills,especiallyobservationalskillsrequiredforanalysis,andaccuratequantitative

techniquesinvolvedindeterminationofenergychangesandreactionrates.

Thereareopportunitiesfordevelopingmathematicalskillswhenstudyingenthalpychangesandreactionratesandwhencarryingoutquantitativepracticalwork.

Synopticassessment

Thismoduleprovidesacontextforsynopticassessment and the subject content links strongly with contentencounteredinModule2:Foundationsinchemistry.

• Atoms, moles and stoichiometry

• Acidandredoxreactions

• Bonding and structure

Knowledge and understanding of Module 2 will be assumedandexaminationquestionswillbesetthatlink its content with this module and other areas of chemistry.

3.1 The periodic table

Periodictrendsarefirststudiedtoextendtheunderstanding of structure and bonding. Group propertiesarethenstudiedusingGroup2andthehalogens as typical metal and non-metal groups respectively,allowinganunderstandingofredoxreactionstobedevelopedfurther.

Finally,thissectionlooksathowunknownioniccompoundscanbeanalysedandidentifiedusingsimple test-tube tests.


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3.1.1 Periodicity



Thestructureoftheperiodictable

(a) the periodic table as the arrangement of elements:(i) by increasing atomic (proton) number(ii) inperiodsshowingrepeatingtrends

inphysicalandchemicalproperties(periodicity)

(iii) ingroupshavingsimilarchemicalproperties

HSW1,7,11 The development of the Periodic Law andacceptancebythescientificcommunity.

HSW7,11 The extension of the periodic table throughdiscoveryandconfirmationofnewelements.

Periodictrendinelectronconfiguration andionisationenergy

(b) (i) theperiodictrendinelectronconfigurationsacross Periods 2 and 3 (see also 2.2.1 d)

(ii) classificationofelementsintos-,p-andd-blocks

(c) firstionisationenergy(removalof1molofelectrons from 1 mol of gaseous atoms) and successiveionisationenergy,and:(i) explanationofthetrendinfirstionisation

energies across Periods 2 and 3, and down a group,intermsofattraction,nuclearchargeand atomic radius

(ii) predictionfromsuccessiveionisationenergies of the number of electrons in each shell of an atom and the group of an element

M3.1

Definitionrequiredforfirstionisationenergyonly. Explanationtoincludethesmalldecreasesasaresult of s- and p-sub-shell energies (e.g. between BeandB)andp-orbitalrepulsion(e.g.betweenNand O).

HSW1,2TrendsinionisationenergysupporttheBohr model of the atom.

Periodictrendinstructureandmeltingpoint

(d) explanationof:(i) metallicbondingasstrongelectrostatic

attractionbetweencations(positiveions)and delocalised electrons

(ii) agiantmetalliclatticestructure,e.g.allmetals

Nodetailsofcubicorhexagonalpackingrequired.

(e) explanationofthesolidgiantcovalentlatticesofcarbon (diamond, graphite and graphene) and silicon as networks of atoms bonded by strong covalent bonds

HSW1,9 Use of ideas about bonding to explain the strengthandconductivepropertiesofgraphene,anditspotentialapplicationsandbenefits.


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(f) explanationofphysicalpropertiesofgiantmetallicandgiantcovalentlattices,includingmeltingandboilingpoints,solubilityandelectricalconductivityintermsofstructureandbonding

Explanationsshouldbeintermsofthetypesofparticlepresentinalattice,therelativestrengthofforcesandbonds,andthemobilityoftheparticlesinvolved, as appropriate.

HSW1 Use of ideas about bonding to explain macroscopicproperties.

(g) explanationofthevariationinmeltingpointsacross Periods 2 and 3 in terms of structure and bonding (see also 2.2.2 o).

M3.1

Trend in structure from giant metallic to giant covalenttosimplemolecularlattice.

3.1.2Group2



Redoxreactionsandreactivityof Group2metals

(a) the outer shell s2electronconfigurationandthelossoftheseelectronsinredoxreactionstoform2+ ions

(b) therelativereactivitiesoftheGroup2elementsMg →Bashownbytheirredoxreactionswith:(i) oxygen(ii) water(iii) dilute acids

Reactionswithacidswillbelimitedtothoseproducing a salt and hydrogen.

(c) thetrendinreactivityintermsofthefirstandsecondionisationenergiesofGroup2elementsdown the group (see also 3.1.1 c)

M3.1

Definitionofsecondionisationenergyisnot required, but learners should be able to write an equationforthechangeinvolved.

ReactionsofGroup2compounds

(d) theactionofwateronGroup2oxidesandtheapproximatepHofanyresultingsolutions,including the trend of increasing alkalinity

(e) uses of some Group 2 compounds as bases, includingequations,forexample(butnotlimitedto):(i) Ca(OH)2 in agriculture to neutralise acid

soils(ii) Mg(OH)2 and CaCO3as‘antacids’intreating

indigestion.


2

3.1.3Thehalogens



Characteristicphysicalproperties

(a) existence of halogens as diatomic molecules and explanationofthetrendintheboilingpointsofCl2, Br2 and I2, in terms of induced dipole–dipole interactions(Londonforces)(seealso2.2.2k)

Redoxreactionsandreactivityof halogensandtheircompounds

(b) the outer shell s2p5electronconfigurationand the gaining of one electron in many redox reactionstoform1–ions

Throughoutthissection,explanationsofredoxreactionsshouldemphasiseelectrontransferandoxidationnumberchangesandincludefullandionicequations(see also 2.1.5 Redox).

(c) thetrendinreactivityofthehalogensCl2, Br2 and I2,illustratedbyreactionwithotherhalideions

Including colour change in aqueous and organic solutions.

(d) explanationofthetrendinreactivityshownin(c), from the decreasing ease of forming 1– ions, intermsofattraction,atomicradiusandelectronshielding

(e) explanationofthetermdisproportionation as oxidationandreductionofthesameelement,illustrated by:(i) thereactionofchlorinewithwaterasused

inwaterpurification(ii) thereactionofchlorinewithcold,dilute

aqueous sodium hydroxide, as used to form bleach

(iii) reactionsanalogoustothosespecifiedin(i) and (ii)

(f) thebenefitsofchlorineuseinwatertreatment(killing bacteria) contrasted with associated risks (e.g. hazards of toxic chlorine gas and possiblerisksfromformationofchlorinatedhydrocarbons)

HSW9,10,12 Decisions on whether or not to chlorinatewaterdependonbalanceofbenefitsandrisks,andethicalconsiderationsofpeople’srighttochoose.Considerationofothermethodsofpurifyingdrinking water.

Characteristicreactionsofhalideions

(g) theprecipitationreactions,includingionicequations,oftheaqueousanionsCl

–, Br– and I– with aqueous silver ions, followed by aqueous ammonia,andtheiruseasatestfordifferenthalide ions.

Complexes with ammonia are not required other thanobservations. PAG4 HSW4Qualitativeanalysis.


2

3.1.4Qualitativeanalysis



Tests for ions

(a) qualitativeanalysisofionsonatest-tubescale; processesandtechniquesneededtoidentifythefollowing ions in an unknown compound:(i) anions:

• CO32–,byreactionwithH+(aq)

forming CO2(g) (see 2.1.4 c)

• SO42–,byprecipitationwithBa2+(aq)

• Cl –, Br–, I– (see3.1.3g)

(ii) cations:NH4+, byreactionwithwarm

NaOH(aq)formingNH3.

Sequence of tests required is carbonate, sulfate then halide. (BaCO3 and Ag2SO4 are both insoluble.)

PAG4 HSW4Qualitativeanalysis.

3.2 Physical chemistry

Thissectionintroducesphysicalchemistrywithinthegeneral theme of energy.

Learnersfirststudytheimportanceofenthalpychanges,theirusesanddeterminationfromexperimental results including enthalpy cycles.

Thissectiontheninvestigatesthe ways in which a changeinconditionscanaffecttherateofachemicalreaction,intermsofactivationenergy,theBoltzmanndistributionandcatalysis.

Reversiblereactionsarethenstudied,includingthe dynamic nature of chemical equilibrium and theinfluenceofconditionsuponthepositionofequilibrium.

Finally, the integrated roles of enthalpy changes, rates, catalysts and equilibria are considered as a way of increasing yield and reducing energy demand, improving the sustainability of industrial processes.

3.2.1Enthalpychanges



Enthalpychanges:∆Hofreaction,formation, combustionandneutralisation

(a) explanationthatsomechemicalreactionsareaccompanied by enthalpy changes that are exothermic(∆H,negative)orendothermic(∆H,positive)

(b) constructionofenthalpyprofilediagramstoshowthedifferenceintheenthalpyofreactantscompared with products

M3.1


2

(c) qualitativeexplanationofthetermactivation energy,includinguseofenthalpyprofilediagrams

M3.1

Activationenergyintermsoftheminimumenergyrequiredforareactiontotakeplace.

(d) explanationanduseoftheterms:(i) standard conditions and standard states

(physicalstatesunderstandardconditions)(ii) enthalpy change of reaction (enthalpy

changeassociatedwithastatedequation,∆rH)

(iii) enthalpy change of formation(formationof 1 mol of a compound from its elements, ∆fH)

(iv) enthalpy change of combustion (complete combustionof1molofasubstance,∆cH)

(v) enthalpy change of neutralisation (formationof1molofwaterfromneutralisation,∆neutH)

Definitionsrequiredforenthalpychangesofformation,combustionandneutralisationonly.

Standardconditionscanbeconsideredas100kPaandastatedtemperature,298K.

(e) determinationofenthalpychangesdirectlyfromappropriate experimental results, including use oftherelationship:q = mc∆T

M0.0, M0.2, M2.2, M2.3, M2.4 PAG3

Bond enthalpies

(f) (i) explanationofthetermaverage bond enthalpy (breaking of 1 mol of bonds in gaseous molecules)

(ii) explanationofexothermicandendothermicreactionsintermsofenthalpychangesassociated with the breaking and making of chemical bonds

(iii) use of average bond enthalpies to calculate enthalpychangesandrelatedquantities(see also 2.2.2 f)

M0.0, M0.2, M2.2, M2.3, M2.4

Definitionofaveragebondenthalpynot required.

Learners are expected to understand that an actual bondenthalpymaydifferfromtheaveragevalue.

Hess’lawandenthalpycycles

(g) Hess’lawforconstructionofenthalpycyclesandcalculationstodetermineindirectly:(i) anenthalpychangeofreactionfrom

enthalpychangesofcombustion(ii) anenthalpychangeofreactionfrom

enthalpychangesofformation(iii) enthalpy changes from unfamiliar enthalpy

cycles

M0.0, M0.2, M1.1, M2.2, M2.3, M2.4, M3.1

DefinitionofHess'lawnot required. Unfamiliar enthalpy cycles will be provided.

HSW2Applicationoftheprincipleofconservationofenergy to determine enthalpy changes.

(h) the techniques and procedures used to determine enthalpy changes directly and indirectly.

M3.1, M3.2

PAG3 HSW4Opportunitiesforcarryingoutexperimentalandinvestigativework.


2

3.2.2Reactionrates



Simple collision theory

(a) theeffectofconcentration,includingthepressureofgases,ontherateofareaction,interms of frequency of collisions

(b) calculationofreactionratefromthegradientsofgraphsmeasuringhowaphysicalquantitychangeswithtime

M3.1, M3.2, M3.5

Suitablephysicalquantitiestomonitorcouldincludeconcentration,gasvolume,mass,etc.

Catalysts

(c) explanationoftheroleofacatalyst:(i) inincreasingreactionratewithoutbeing

usedupbytheoverallreaction(ii) inallowingareactiontoproceedviaa

differentroutewithloweractivationenergy,asshownbyenthalpyprofilediagrams

Details of processes are not required.

(d) (i) explanationofthetermshomogeneous and heterogeneous catalysts

(ii) explanationthatcatalystshavegreateconomicimportanceandbenefitsforincreased sustainability by lowering temperatures and reducing energy demand fromcombustionoffossilfuelswithresultingreductioninCO2 emissions

HSW9,10Benefitstotheenvironmentofimprovedsustainability weighed against toxicity of some catalysts.

(e) the techniques and procedures used to investigatereactionratesincludingthemeasurementofmass,gasvolumesandtime


TheBoltzmanndistribution

(f) qualitativeexplanationoftheBoltzmanndistributionanditsrelationshipwithactivationenergy (see also 3.2.1 c)

M3.1

(g) explanation,usingBoltzmanndistributions,ofthequalitativeeffectontheproportionofmoleculesexceedingtheactivationenergyandhencethereactionrate,for:(i) temperature changes(ii) catalyticbehaviour(see also 3.2.2 c).

M3.1

HSW1,2,5UseofBoltzmanndistributionmodeltoexplaineffectonreactionrates.


2

3.2.3Chemicalequilibrium



DynamicequilibriumandleChatelier’sprinciple

(a) explanationthatadynamicequilibriumexistsin a closed system when the rate of the forward reactionisequaltotherateofthereversereactionandtheconcentrationsofreactantsandproducts do not change

(b) leChatelier’sprincipleanditsapplicationforhomogeneousequilibriatodeducequalitativelytheeffectofachangeintemperature,pressureorconcentrationonthepositionofequilibrium

DefinitionforleChatelier'sprinciplenot required.

HSW1,2,5 Use of le Chatelier’s principle to explain effectoffactorsonthepositionofequilibrium.

(c) explanationthatacatalystincreasestherateofbothforwardandreversereactionsinanequilibriumbythesameamountresultinginanunchangedpositionofequilibrium

(d) the techniques and procedures used to investigatechangestothepositionofequilibriumforchangesinconcentrationandtemperature.

Qualitativeeffectsonly.

HSW4Opportunitiestocarryoutexperimentalandinvestigativework.

(e) explanationoftheimportancetothechemicalindustry of a compromise between chemical equilibriumandreactionrateindecidingtheoperationalconditions

HSW6Balancingtheeffectsofequilibrium,rate,safetyandeconomicstodeterminetheconditionsusedinindustrialreactionse.g.Haberprocess.

Theequilibriumconstant,Kc

(f) expressions for the equilibrium constant, Kc ,forhomogeneousreactionsandcalculationsof the equilibrium constant, Kc ,fromprovidedequilibriumconcentrations

M0.2, M1.1, M2.3, M2.4

Learners will not need to determine the units for Kc.

(g) estimationofthepositionofequilibriumfromthe magnitude of Kc.

M0.3

Aqualitativeestimationonlyisrequired.


2

Module4:Coreorganicchemistry

This module introduces organic chemistry and its importantapplicationstoeverydaylife,includingcurrent environmental concerns associated with sustainability.

The module assumes knowledge and understanding of the chemical concepts developed in Module 2: Foundationsinchemistry.

The module provides learners with a knowledge and understanding of the important chemical ideas that underpin the study of organic chemistry:

• nomenclatureandformularepresentation,functionalgroups,organicreactionsandisomerism

• aliphatichydrocarbons

• alcohols and haloalkanes

• organicpracticalskillsandorganicsynthesis

• instrumentalanalyticaltechniquestoprovideevidence of structural features in molecules.

This module also provides learners with an opportunity todevelopimportantorganicpracticalskills,includinguseofQuickfitapparatusfordistillation,heatingunderrefluxandpurificationoforganicliquids.

In the context of this module, it is important that learners should appreciate the need to consider responsible use of organic chemicals in the environment. Current trends in this context include reducing demand for hydrocarbon fuels, processing plasticwasteproductively,andpreventinguseofozone-depletingchemicals.

Synopticassessment

Thismoduleprovidesacontextforsynopticassessment and the subject content links strongly with thecontentencounteredinModule2:Foundationsinchemistry.

• Atoms, moles and stoichiometry

• Acidandredoxreactions

• Bonding and structure

Knowledge and understanding of Module 2 will be assumedandexaminationquestionswillbesetthatlink its content with this module and other areas of chemistry.

4.1 Basic concepts and hydrocarbons

Thissectionisfundamentaltothestudyoforganicchemistry.

Thissectionintroducesthevarioustypesofstructuresusedroutinelyinorganicchemistry,nomenclature,and the important concepts of homologous series,

functionalgroups,isomerismandreactionmechanismsusing curly arrows.

Theinitialideasarethendevelopedwithinthecontextof the hydrocarbons: alkanes and alkenes.


2

4.1.1Basicconceptsoforganicchemistry



Namingandrepresentingtheformulae oforganiccompounds

(a) applicationofIUPACrulesofnomenclatureforsystematicallynamingorganiccompounds

Nomenclaturewillbelimitedtothefunctionalgroupswithinthisspecification. E.g. CH3CH2CH(CH3)CH2OHhasthesystematicname: 2-methylbutan-1-ol. Learners will be expected to know the names of the firsttenmembersofthealkaneshomologousseriesand their corresponding alkyl groups.

HSW8Useofsystematicnomenclaturetoavoidambiguity. HSW11TheroleofIUPACindevelopingasystematicframework for chemical nomenclature.

(b) interpretationanduseoftheterms:(i) general formula (the simplest algebraic

formula of a member of a homologous series) e.g. for an alkane: CnH2n+2

(ii) structural formula (the minimal detail that shows the arrangement of atoms in a molecule) e.g. for butane: CH3CH2CH2CH3 or CH3(CH2)2CH3

(iii) displayed formula(therelativepositioningof atoms and the bonds between them) e.g. for ethanol:

H

C

H

H

C

H

H O H

(iv) skeletal formula (thesimplifiedorganicformula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbonskeletonandassociatedfunctionalgroups) e.g. for butan-2-ol:

OH

M4.2

See also 2.1.3 b for empirical formula and molecular formula. Definitionsnot required.

In structural formulae, the carboxyl group will be represented as COOH and the ester group as COO.

The symbols below will be used for cyclohexane and benzene:

HSW8Communicationusingorganicchemicalstructures;selectingtheappropriatetypeofformulafor the context.


2

Functionalgroups

(c) interpretationanduseoftheterms:(i) homologous series (a series of organic

compoundshavingthesamefunctionalgroup but with each successive member differingbyCH2)

(ii) functional group (a group of atoms responsibleforthecharacteristicreactionsof a compound)

(iii) alkyl group (of formula CnH2n+1)(iv) aliphatic (a compound containing carbon

and hydrogen joined together in straight chains,branchedchainsornon-aromaticrings)

(v) alicyclic(analiphaticcompoundarrangedinnon-aromaticringswithorwithoutsidechains)

(vi) aromatic (a compound containing a benzene ring)

(vii) saturated (single carbon–carbon bonds only) and unsaturated (the presence of multiplecarbon–carbonbonds,includingC=C, C/Candaromaticrings)

Definitionrequiredforhomologousseriesonly.

R may be used to represent alkyl groups, but also other fragments of organic compounds not involved inreactions.

The terms saturated and unsaturated will be used toindicatethepresenceofmultiplecarbon–carbonbondsasdistinctfromthewiderterm‘degreeofsaturation’usedalsoforanymultiplebondsandcyclic compounds.

(d) use of the general formula of a homologous series to predict the formula of any member of the series

Isomerism

(e) explanationofthetermstructural isomers (compounds with the same molecular formulabutdifferentstructuralformulae)anddeterminationofpossiblestructuralformulaeofan organic molecule, given its molecular formula

M4.2

Reactionmechanisms

(f) thedifferenttypesofcovalentbondfission:(i) homolyticfission(intermsofeachbonding

atom receiving one electron from the bonded pair, forming two radicals)

(ii) heterolyticfission(intermsofonebondingatom receiving both electrons from the bonded pair)


2

(g) the term radical (a species with an unpaired electron) and use of ‘dots’ to represent species that are radicals in mechanisms

Radical mechanisms will be represented by a sequenceofequations. Dots, •, are required in all instances where there is a single unpaired electron (e.g. Cl • and CH3•). Dots are not required for species that are diradicals (e.g. O).

(h) a ‘curly arrow’ described as the movement of an electronpair,showingeitherheterolyticfissionorformationofacovalentbond

‘Half curly arrows’ are not required, see 4.1.2 f.

HSW1,8Useofthe‘curlyarrow’modeltodemonstrateelectronflowinorganicreactions.

(i) reactionmechanisms,usingdiagrams,toshowclearly the movement of an electron pair with ‘curly arrows’ and relevant dipoles.

Any relevant dipoles should be included. Curly arrows should start from a bond, a lone pair of electronsoranegativecharge.

HSW1,2,8Useofreactionmechanismstoexplainorganicreactions.

4.1.2Alkanes



Propertiesofalkanes

(a) alkanes as saturated hydrocarbons containing singleC–CandC–Hbondsasσ-bonds(overlapof orbitals directly between the bonding atoms); freerotationoftheσ-bond

Hybridisationnot required.

HSW1 Use of model of orbital overlap to explain covalent bonding in organic compounds.

(b) explanationofthetetrahedralshapeandbond angle around each carbon atom in alkanes in terms of electron pair repulsion (seealso2.2.2g–h)

M4.1, M4.2

Learners should be able to draw 3-D diagrams.

(c) explanationofthevariationsinboilingpointsofalkaneswithdifferentcarbon-chainlengthandbranching, in terms of induced dipole–dipole interactions(Londonforces)(seealso2.2.2k)

M3.1

Reactionsofalkanes

(d) thelowreactivityofalkaneswithmanyreagentsin terms of the high bond enthalpy and very low polarityoftheσ-bondspresent(see also 2.2.2 j)

HSW1 Use of ideas about enthalpy and polarity to explainmacroscopicpropertiesofalkanes.

(e) completecombustionofalkanes,asusedinfuels,andtheincompletecombustionofalkanefuelsinalimitedsupplyofoxygenwiththeresultingpotentialdangersfromCO


2

(f) thereactionofalkaneswithchlorineandbrominebyradicalsubstitutionusingultravioletradiation,includingamechanisminvolvinghomolyticfissionandradicalreactionsintermsofinitiation,propagationandtermination(see also4.1.1f–g)

Learners are not required to use ‘half curly arrows’ in this mechanism. Equationsshouldshowwhichspeciesareradicalsusing a single ‘dot’, •, to represent the unpaired electron.

(g) thelimitationsofradicalsubstitutioninsynthesisbytheformationofamixtureoforganicproducts,intermsoffurthersubstitutionandreactionsatdifferentpositionsinacarbonchain.

4.1.3Alkenes



Propertiesofalkenes

(a) alkenes as unsaturated hydrocarbons containing aC=Cbondcomprisingaπ-bond(sidewaysoverlap of adjacent p-orbitals above and below thebondingCatoms)andaσ-bond(overlapoforbitals directly between the bonding atoms) (see also 4.1.2 a);restrictedrotationoftheπ-bond

Hybridisationisnot required.

HSW1 Use of model of orbital overlap to explain covalent bonding in organic compounds.

(b) explanationofthetrigonalplanarshapeandbond angle around each carbon in the C=C of alkenes in terms of electron pair repulsion (see also2.2.2g–h,4.1.2b)

M4.1, M4.2


2

Stereoisomerisminalkenes

(c) (i) explanationoftheterms: • stereoisomers (compounds with the

same structural formula but with a differentarrangementinspace)

• E/Z isomerism (an example of stereoisomerism, in terms of restrictedrotationaboutadoublebond and the requirement for two differentgroupstobeattachedtoeach carbon atom of the C=C group)

• cis–trans isomerism (a special case of E/Z isomerism in which two of the substituentgroupsattachedtoeachcarbon atom of the C=C group are the same)

(ii) use of Cahn–Ingold–Prelog (CIP) priority rulestoidentifytheE and Z stereoisomers

M4.2, M4.3

C C

H

HE-but-2-ene

(trans)Z-but-2-ene

(cis)

CH3

H3C

H3C

C C

H

CH3

H

Use of E as equivalent to trans and Z as equivalent to cis is only consistently correct when there is an H on each carbon atom of the C=C bond.

AssigningCIPprioritiestodoubleortriplebondswithin R groups is not required:

C C

R''

R' R'''

R

(d) determinationofpossibleE/Z or cis–trans stereoisomers of an organic molecule, given its structural formula

M4.2, M4.3

Additionreactionsofalkenes

(e) thereactivityofalkenesintermsoftherelativelylow bond enthalpy of the π-bond

(f) additionreactionsofalkeneswith:(i) hydrogen in the presence of a suitable

catalyst,e.g.Ni,toformalkanes(ii) halogens to form dihaloalkanes, including

the use of bromine to detect the presence of a double C=C bond as a test for unsaturationinacarbonchain

(iii) hydrogen halides to form haloalkanes(iv) steam in the presence of an acid catalyst,

e.g. H3PO4, to form alcohols

(g) definitionanduseofthetermelectrophile (an electron pair acceptor)

(h) themechanismofelectrophilicadditioninalkenesbyheterolyticfission(seealso4.1.1h–i)

Forthereactionwithhalogens,eitheracarbocationor a halonium ion intermediate is acceptable.

HSW1,2,8Useofreactionmechanismstoexplainorganicreactions.


2

(i) useofMarkownikoff’sruletopredictformationofamajororganicproductinadditionreactionsof H–X to unsymmetrical alkenes, e.g. H–Br to propene,intermsoftherelativestabilitiesofcarbocationintermediatesinthemechanism

Limitedtostabilitiesofprimary,secondaryandtertiarycarbocations. Explanationforrelativestabilitiesofcarbocationsnot required.

HSW1,2,5 Use of stability to explain products of organicreactions.

Polymersfromalkenes

(j) additionpolymerisationofalkenesandsubstitutedalkenes,including:(i) therepeatunitofanadditionpolymer

deduced from a given monomer(ii) identificationofthemonomerthatwould

produceagivensectionofanadditionpolymer

Wastepolymersandalternatives

(k) thebenefitsforsustainabilityofprocessingwastepolymers by:(i) combustionforenergyproduction(ii) use as an organic feedstock for the

productionofplasticsandotherorganicchemicals

(iii) removal of toxic waste products, e.g. removal of HCl formed during disposal bycombustionofhalogenatedplastics(e.g. PVC)

HSW9,10Benefitsofcheapoil-derivedplasticscounteracted by problems for environment of landfill;themovetore-usingwaste,improvinguseof resources.

(l) thebenefitstotheenvironmentofdevelopmentof biodegradable and photodegradable polymers.

HSW9,10Benefitsofreduceddependencyonfiniteresourcesandalleviatingproblemsfromdisposalofpersistentplasticwaste.


2

4.2Alcohols,haloalkanesandanalysis

Thissectionintroducestwofurtherfunctionalgroups: alcohols and haloalkanes, and considers the importance of polarity and bond enthalpy to organic reactions.

Throughoutthissection,therearemanyopportunitiesfordevelopingorganicpracticalskills,includingpreparationandpurificationoforganicliquids.

Finally, the important techniques of infrared spectroscopy and mass spectrometry are used to illustrate instrumental analysis as a valuable tool for identifyingorganiccompounds.

4.2.1 Alcohols



Propertiesofalcohols

(a) (i) thepolarityofalcoholsandanexplanation,in terms of hydrogen bonding, of the water solubilityandtherelativelylowvolatilityofalcohols compared with alkanes (see also 2.2.2 l and 4.1.2 c)

(ii) classificationofalcoholsintoprimary,secondaryandtertiaryalcohols

Reactionsofalcohols

(b) combustionofalcohols

(c) oxidationofalcoholsbyanoxidisingagent,e.g. Cr2O7

2–/H+ (i.e. K2Cr2O7/H2SO4), including:(i) theoxidationofprimaryalcoholstoform

aldehydes and carboxylic acids; the control oftheoxidationproductusingdifferentreactionconditions

(ii) theoxidationofsecondaryalcoholstoformketones

(iii) theresistancetooxidationoftertiaryalcohols

Equationsshoulduse[O]torepresenttheoxidisingagent.

PAG7

(d) eliminationofH2O from alcohols in the presence of an acid catalyst (e.g. H3PO4 or H2SO4) and heat to form alkenes

Mechanism not required.

(e) substitutionwithhalideionsinthepresenceofacid(e.g.NaBr/H2SO4) to form haloalkanes.

Mechanism not required.


2

4.2.2Haloalkanes



Substitutionreactionsofhaloalkanes

(a) hydrolysisofhaloalkanesinasubstitutionreaction:(i) by aqueous alkali(ii) bywaterinthepresenceofAgNO3 and

ethanol to compare experimentally the ratesofhydrolysisofdifferentcarbon–halogen bonds

PAG7

(b) definitionanduseofthetermnucleophile (an electron pair donor)

(c) themechanismofnucleophilicsubstitutioninthehydrolysis of primary haloalkanes with aqueous alkali (seealso4.1.1h–i)

HSW1,2Useofreactionmechanismstoexplainorganicreactions.

(d) explanationofthetrendintheratesofhydrolysisof primary haloalkanes in terms of the bond enthalpies of carbon–halogen bonds (C–F, C–Cl, C–Br and C–I)

Environmentalconcernsfromuseoforganohalogencompounds

(e) productionofhalogenradicalsbytheactionofultraviolet(UV)radiationonCFCsintheupperatmosphereandtheresultingcatalysedbreakdownoftheEarth’sprotectiveozonelayer,includingequationstorepresent:(i) theproductionofhalogenradicals(ii) the catalysed breakdown of ozone by Cl •

andotherradicalse.g.•NO.

Simpleequationsofthebreakdownprocessarerequired, e.g. C2F2Cl2 → C2F2Cl • + •Cl •Cl + O3 → •Cl O + O2 •Cl O + O → •Cl + O2 Learners could be expected to construct similar equationsforotherstatedradicals.

HSW9,10,11,12BenefitsofCFCs;acceptanceofscientificevidenceexplainingozonedepletionleadingtogovernmentlegislationagainstCFCuse.


2

4.2.3Organicsynthesis



Practicalskills

(a) the techniques and procedures for:(i) useofQuickfitapparatusincludingfor

distillationandheatingunderreflux(ii) preparationandpurificationofanorganic

liquid including: • useofaseparatingfunneltoremove

an organic layer from an aqueous layer

• drying with an anhydrous salt (e.g. MgSO4, CaCl2)

• redistillation

PAG5 HSW4Opportunitiestocarryoutexperimentalandinvestigativework.

Syntheticroutes

(b) for an organic molecule containing several functionalgroups:(i) identificationofindividualfunctionalgroups(ii) predictionofpropertiesandreactions

Learnerswillbeexpectedtoidentifyfunctionalgroupsencounteredinthisspecification:alkanes,alkenes, alcohols and haloalkanes.

HSW3Developmentofsyntheticroutes.

(c) two-stagesyntheticroutesforpreparingorganiccompounds.

Learners will be expected to be able to devisetwo-stagesyntheticroutesbyapplyingtransformationsbetweenallfunctionalgroupsstudiedinthisspecification.

Extrainformationmaybeprovidedonexampaperstoextendthelearner’stoolkitoforganicreactions.

HSW3Developmentofsyntheticroutes.


2

4.2.4Analyticaltechniques



Infrared spectroscopy

(a) infrared(IR)radiationcausescovalentbondstovibrate more and absorb energy

(b) absorptionofinfraredradiationbyatmosphericgases containing C=O, O–H and C–H bonds (e.g. H2O, CO2 and CH4), the suspected link to global warmingandresultingchangestoenergyusage

HSW9,10,11,12Acceptanceofscientificevidenceexplaining global warming has prompted governments towards policies to use renewable energy supplies.

(c) use of an infrared spectrum of an organic compoundtoidentify:(i) analcoholfromanabsorptionpeakofthe

O–H bond(ii) analdehydeorketonefromanabsorption

peak of the C=O bond(iii) acarboxylicacidfromanabsorptionpeakof

theC=Obondandabroadabsorptionpeakof the O–H bond

M3.1

Inexaminations,infraredabsorptiondatawillbeprovided on the Data Sheet. Learners should be aware that most organic compounds produce a peak at approximately 3000 cm–1duetoabsorptionbyC–Hbonds.

(d) interpretationsandpredictionsofaninfraredspectrum of familiar or unfamiliar substances using supplied data

M3.1

Restrictedtofunctionalgroupsstudiedinthisspecification.

HSW3,5Analysisandinterpretationofspectra.

(e) use of infrared spectroscopy to monitor gases causingairpollution(e.g.COandNOfromcaremissions) and in modern breathalysers to measure ethanol in the breath

HSW12Useofanalyticaltechniquestoprovideevidence for law courts, e.g. drink driving.

Mass spectrometry

(f) use of a mass spectrum of an organic compound toidentifythemolecularionpeakandhencetodetermine molecular mass

M3.1

Limited to ions with single charges. Mass spectra limited to organic compounds containing C, H and O encountered in this specification.

Learners should be aware that mass spectra may containasmallM+1peakfromthesmallproportionof carbon-13.



2

(g) analysisoffragmentationpeaksinamassspectrumtoidentifypartsofstructures

M3.1

Learners should be able to suggest the structures of fragment ions.


Combinedtechniques

(h) deductionofthestructuresoforganiccompoundsfromdifferentanalyticaldataincluding:(i) elemental analysis (see also 2.1.3 c)(ii) mass spectra(iii) IR spectra.

M3.1

Limitedtofunctionalgroupsencounteredinthisspecification.

Learners will not be expected to interpret mass spectra of organic halogen compounds.

HSW3,5,6Analysisandinterpretationofdifferentanalyticaldata.

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OCR AS Level in Chemistry A (H032) - BioChem Tuition · PDF fileOCR AS Level in Chemistry A (H032) ... How To Achieve Grade ‘A’ ... science courses at GCSE level. This module provides