Thefirstgasescamefromtheerup1onofVolcanoesandformedtheEarth’searlyatmosphere.Themaingasesintheearlyatmospherewere:•  Lotsofcarbondioxide•  Somenitrogen•  Li>leornooxygen•  Watervapour•  Ammonia

Volcanoesreleasethesegasestoday(andsoscien1ststhinkthesameprocessesoperatedinthepast).

C1.1TheEarlyatmosphere

Theoceanswereformedfromthecondensa1onofthewatervapourtomakeliquidwater.

C1.2achangingatmosphere.

AsimplecarboncycleThelevelofcarbondioxideintheatmosphereismaintainedbyseveralprocesses,photosynthesis,respira1onandcombus1onGreenplantsremovecarbondioxidefromtheatmospherebyphotosynthesis.Respira1onandcombus1onbothreleasecarbondioxideintotheatmosphere.Theseprocessesformacarboncycleinwhichthepropor1onofcarbondioxideintheatmosphereremainsaboutthesame.

Carbondioxidefellbecause:•  Somecarbondioxide

dissolvedintotheoceans.•  Somewasabsorbedby

marinecreatureswhostoredit1ntheirshellsascalciumcarbonatewhichlaterformedcarbonaterocks.

Asthenumberofplantsincreased,theoxygenlevelsrosethroughphotosynthesis.Theseplantsabsorbcarbondioxidetoo.

CarbondioxidelevelsfellOxygenlevelsrose

C1.4Theatmospheretoday.

Changesintheatmosphereoccurthrough;Naturalac9vi9es:•  Volcanicac1vitycanleadtoarisein

sulphurdioxide;lighteningcanleadtoariseinnitrogenoxides.

Humanac9vity:•  burningfossilfuelscanleadtoan

increaseofcarbondioxide,carbonmonoxideandsulphurdioxide.

•  Deforesta9onleadtoanincreaseincarbondioxide;burningtreesreleasescarbondioxide(combus1on),fewertreestophotosynthesiseandabsorbcarbondioxide;enginesandfurnacesreleasenitrogenoxides.

•  Farming:increasingnumbersofca>leandricefieldscanleadtoanincreaseofmethane.

Howdoscien9stsuserockstoworkoutthecomposi9onoftheEarth’searlyatmosphere?Analysethemineralsinthemandlookforoxides.Asmoreoxygenwaspresent,moreoxidemineralswereformed.

Gas Formula %indryair

Nitrogen N2 78

Oxygen O2 21

Argon Ar 0.9

CarbonDioxide

CO2 0.04

other trace

Ouratmospheretoday…

C1.5RocksandtheirForma1onIgneousRocks•  Example–granite.•  Formedbythesolidifica1onof

magmaorlava•  Theycontaincrystalswhose

sizedependsontherateofcooling.

•  Quickcooling=smallcrystals•  Fastcooling=largecrystals

l metamorphic–Arockchangedbypressureandheat.l sedimentary–Arockformedbythedeposi1onofsediments.l thermaldecomposi1on–Thebreakdownofacompoundintosimplersubstancesbyhea1ng.l electrolysis–Theuseofelectricitytosplitacompound.l granite–Atypeofigneousrockthatisharderthanlimestoneandmarble.l igneous–Arockformedfromcooledmagna.l limestone–Atypeofsedimentaryrockcontainingcalciumcarbonate.l limewater–Alimestoneproductmadebyfullydissolvingquicklimeinwater.Itisusedtotestforcarbondioxide.l marble–Atypeofmetamorphicrockthatisharderthanlimestonebutso^erthangranite

Sedimentaryrocks•  Sedimentaryrockscontainfossils•  Theyareformedfromcompac1onof

layersofrockoveralong1me.•  Theyarenotasstrongasotherrocksso

erodeeasily.•  Examples-chalkandlimestone

MetamorphicRocks•  Example–marble•  Formedwhenheator

pressureisappliedtootherrocks.

•  Marbleisformedfromchalkorlimestonebeingheatedandpressurised.

Limestone,chalkandmarbleareallformsofcalciumcarbonateandexistintheEarthscrust.

C1.6LimestoneLimestoneismadeofcalciumcarbonate(CaCO3)Itisusedin:

–  Buildingmaterials-glass,cement,concrete–  ImprovingthepHofacidsoil

ThermalDecomposi1onofCalciumCarbonateWhenmetalcarbonatesareheatedtheybreakdownintoametaloxideandcarbondioxideisgivenoffCoppercarbonateàcopperoxide+carbondioxideCaCO3CaO+CO2

Problemsassociatedwithquarrying:Economic-moneySocial–thepeopleEnvironmental-pollu1on

LimestoneisheatedwithclaytomakecementCementisaddedtosandandwatertomakemortarCementisaddedtosand,aggregateandwatertomakeconcreteAdvantageofquarrying…jobsandvaluablebuildingresources.

Theadvantagesanddisadvantagesofquarrying.

C1.7Thermaldecomposi1onEaseofthermaldecomposi1onofmetalcarbonates:•  Mostdifficulttodecomposeissodiumcarbonate(10000C),calciumcarbonate(8250C),zinc

carbonate(3000C)andcoppercarbonate(2000C).

•  Coppercarbonatewillstarttodecomposetoformcarbondioxideandcopperoxide.Thereac1onwillabsorbsomeoftheheatfromthefire.Thecarbondioxidecanhelptoputoutthefirebyreducingtheamountofoxygenavailableforcombus1on.

•  Themassofreactantsdonotchange,thepar1clesjustgetrearranged.•  Theatomstakepartinachemicalreac1ontheyareverysmall.•  WhencalciumhydroxideisdissolvedinwateritmakesLimewater.

Coppercarbonateàcopperoxide+carbondioxideCaCO3(s)àCaO(s)+CO2(g)

Coppercarbonateàcopperoxide+carbondioxideZinccarbonateàzincoxide+carbondioxide

Breakingdownwithheat

C1.8Chemicalreac1ons

Wordequa9onsAwordequa1ongivesthenamesofthesubstancesinvolvedinareac1on.Forexample:

copper+oxygen→copper(II)oxideCopperandoxygenarethereactants,andcopper(II)oxideistheproduct.

Precipita9onreac9ons1)Asimpleexampleofconserva1onofmassisaprecipita9onreac1on.2)Transi1onmetalsformcolouredcompoundswithotherelements.Manyofthesearesolubleinwater,formingcolouredsolu1ons.Ifsodiumhydroxidesolu1onisthenadded,atransi1onmetalhydroxideisformed.Theseareinsoluble.Theydonotdissolvebutinsteadformsolidprecipitates.Asallthereactantsandproductsremaininthesealedreac1oncontainerthenitiseasytoshowthatthetotalmassisunchanged.

coppersulfate+sodiumhydroxide→copperhydroxide+sodiumsulfate

CuSO4+2NaOH→Cu(OH)2+Na2SO4

C1.9Reac1onsofCalciumCompounds

Neutralisingacidswithlimestone1.   Calciumcompoundsthatneutraliseacids:

–  Calciumcarbonate(CaCO3)–  Calciumoxide(CaO)–  Calciumhydroxide(Ca(OH)2)

2.  Usesofthesealkalis1.   Farmersneutralisesoil2.   Powersta9onsusewetpowderedCaCO3toneutraliseacidicwastegaseslikeSulfurdioxideand

nitrousoxides.(belowistheequa9onforsulfurdioxideproduc9on) S(g)+O(g) SO2(g)

Keywords•  Neutralisa9onreac9on-reac1oninwhichabaseoranalkalireactswith

anacid.•  Limewater–Solu1onofcalciumhydroxide.Itisusedtotestforthe

presenceofCO2asitturnsfromcolourlesstocloudy.

MakingLimewater1.   Hea9nglimestone-Calciumcarbonate(CaCO3)turnsitintoCalciumoxide(CaO)

CaCO3(s) CaO(s) +CO2(g)

2.   AddingwatertoCaO–vigorousreac1onthatcreatescalciumhydroxide(crumblysolid)CaO(s)+H2O(l) Ca(OH)2(s)

Tes9ngforCO2-limewaterturnscloudy/milkyascalciumcarbonateforms.Ca(OH)2(s)+CO2(g)CaCO3(s)+H2O(l)NB–largequan99esofCO2willdissolvetoformanacid.ThisreactswiththeCaCO3makingitcolourlessagain!

1.10indiges1onIndiges9onremediescontainsubstancestoneutraliseexcessstomachacid.

•  Whenanacidiccompounddissolvesinwateritproduceshydrogenions,H+.Theseionsareresponsiblefortheacidityofthesolu1on.

•  Whenanalkalinecompounddissolvesinwateritproduceshydroxideions,OH−.Theseionsareresponsibleforthealkalinityofthesolu1on.

•  Acidsreactwithalkalistoformsalts.Thesearecalledneutralisa9onreac9ons.Ineachreac1on,waterisalsoformed:

Acid+alkali→salt+water

ExampleHydrochloricacid+sodiumhydroxide→sodiumchloride+water

HCl+NaOH→NaCl+H2O

•  Hydrochloricacidcontainshydrogenionsandchlorideionsdissolvedinwater.

•  Sodiumhydroxidesolu1oncontainssodiumionsandhydroxideionsdissolvedinwater.

Hydrochloricacidisproducedinthestomachtokillbacteriaandtohelpdiges1on.

Hydrochloricacidproduceschloridesaltse.g.calciumchlorideNitricacidproducesnitratesaltse.g.calciumnitrateSulfuricacidproducessulfatesaltse.g.calciumsulfate

C1.11Neutralisa9on•  Youneedtobeabletodescribethereac1onsofhydrochloricacidandsulfuricacidwith

metalhydroxides,metaloxidesandmetalcarbonates.

Metalhydroxides•  Metalhydroxides,suchassodiumhydroxide,usuallydissolveinwatertoformclear,

colourlesssolu1ons.Whenanacidreactswithametalhydroxide,theonlyproductsformedareasaltpluswater.Hereisthegeneralwordequa1onforthereac1on:

acid+metalhydroxide→asalt+water•  thereisatemperaturerise•  thepHofthereac1onmixturechangesMetaloxides•  Somemetaloxides,suchassodiumoxide,dissolveinwatertoformclear,colourless

solu1ons.Manyofthemarenotsolubleinwater,buttheywillreactwithacids.Copper(II)oxideislikethis.Whenanacidreactswithametaloxide,theonlyproductsformedareasaltpluswater.Hereisthegeneralwordequa1onforthereac1on:

acid+metaloxide→asalt+waterMetalcarbonates•  Althoughsodiumcarbonatecandissolveinwater,mostmetalcarbonatesarenotsoluble.

Calciumcarbonate(chalk,limestoneandmarble)islikethis.Whenanacidreactswithametalcarbonate,theproductsformedareasaltpluswater,butcarbondioxideisalsoformed.Hereisthegeneralwordequa1onforthereac1on:

acid+metalcarbonate→asalt+water+carbondioxide•  Youusuallyobservebubblesofgasbeinggivenoffduringthereac1on.Youcanshowthatthe

gasiscarbondioxidebybubblingitthrough

c1.13electrolysis

Theprocessofelectrolysis•  Posi1velychargedionsmovetothe

nega1veelectrodeduringelectrolysis.Theyreceiveelectronsandarereduced.

•  Nega1velychargedionsmovetotheposi1veelectrodeduringelectrolysis.Theyloseelectronsandareoxidised.

ELECTROLYSISOFHydrochloricAcid•  Produceschlorineattheposi1ve

electrode•  Produceshydrogenatthenega1ve

electrode

ElectrolysisTheprocessinwhichelectricalenergyfromad.c.supplydecomposescompounds

C1.14theimportanceofchlorine/Productsfromsodiumchloride

Learnallofthis

1.15ElectrolysisofWater

Water•  Producesoxygenattheposi1ve

electrode•  Produceshydrogenatthe

nega1veelectrode•  Ifthegasrelightsaglowing

splint,itisoxygen.

ElectrolysisofSeawater•  Thisproduceschlorinegasat

theelectrode.

1.16oresGoldandpla1numfoundnaturallyintheenvironmentastheyareunreac1ve.Mostmetalsarefoundasores(usuallyreactedwithoxygen)intheEarthscrust.Oresarerockswhichcontainmetals.Extrac9on=geqngthemetaloutoftherock.Some1mesyoucan…•  Heattherocktogetthemetal•  Oruseelectrolysis.

Usesofmetals.Gold=jewelleryCopper=wiresSilver=jewellery

C1.26AcidrainEffectsofacidrain-  Fishnumbersstartedtodecrease.-  Soilsaremadeacidandcanharmplants.-  Treesdamaged-  Erosionofbuildingsmadeoflimestone.

Causesofacidrain.-  Dissolvedcarbondioxideandacidicgasesin

water.-  Sulphurdissolvedinwaterfromfossilfuels.-  Burningoffossilfuelswhichcreatesulphur.

C1.17Extrac1ngmetal

l  anode–Theposi1veelectrodeusedinelectrolysis.l  cathode–Thenega1veelectrodeusedinelectrolysis.l  electrolysis–Theuseofanelectriccurrenttoseparate

outtheelementsinacompound.

l  electrolyte–Anioniccompoundthatconductselectricitywheninaliquidstate.

l  ore–Arockthatcontainsametalcombinedwithotherelementsinconcentra1onsthatmakeitprofitabletomine.

Factorswhichaffecthowametalisextractedarecostandposi1oninthereac1vityseries

Ironisheatedwithcarboninareduc1onreac1ontoextractitfromitsore.

Ironoxide+carbonàiron+carbon

dioxide

Aluminiumisextractedfromitsorebyelectrolysisbecauseitismorereac1ve.

Aluminiumoxideàaluminium+oxygen

C1.18Oxida1onandreduc1on

KeywordsReduc9on–occurswhenoxygenisremovedfromacompoundCorrosion–whenametalisconvertedtoitsoxidebytheac1onofmoistairOxida9on–occurswhenoxygenisaddedtoanelementorcompoundRus9ng–thecorrosionofiron

Metalextrac9onisreduc9on•  Mostmetaloresare‘oxides’•  Togetthemetalwemustremovetheoxygen

•  Wesaythecompoundhasbeenreduced.ItisaREDUCTIONreac1on•  Example1=IronoxideisheatedwithCarbon

Ironoxide+Carbon Iron+Carbondioxide•  Example2=Aluminiumisobtainedbyelectrolysisofaluminiumoxide

Aluminiumoxide Aluminium+Oxygen

Corrosionofmetalsisoxida9on

•  Mostmetalscorrode•  Surfaceofametalreactswithoxygen(orsome1meswater)

•  ThisiscalledOXIDATIONreac1on•  Morereac9vemetalscorrodemorerapidly(lessreac9vemaynotcorrodeatalle.g.Gold)•  Alayerofmetaloxideforms(thiscanstopfurthercorrosione.g.onAluminium=andAl2O3layer

forms)

C1.19RecyclingmetalsKeywords•  Recycledmetal–whenausedmetalismelteddownandmade

intosomethingnew.

Manymetalscanberecycled…Advantages•  Naturalreserveswilllastlonger•  Mostuselessenergytorecyclethattoextract.E.g.Aluminiumrecycling95%moreenergy

efficientcomparedtoextrac1on.•  Reducedminingwhichdamageslandscapesandcausespollu1on(dustandnoise)•  Recyclingproduceslesspollu9on.Examplessuppor1ngthisare

•  Leadfromitsore‘galena’producessulfurdioxide•  Carbondioxideisproducedduringextrac1onbyelectrolysis.

Disadvantages•  Costsmoneyandusesenergytocollect,sortandtransportmetalstoberecycled•  Thiscanmakeitmoreexpensivetorecyclesomemetalstheextractthem

ThemostrecycledmetalsintheUKareLead,IronandAluminiumandCopper

Method1.  Collec1ng–requirespeopletobewillingtoseparatetheirrubbish2.  Separa1ngdifferentmetals

•  Ironcanbeseparatedusingamagnet(quickandeasy)•  Othersusuallyseparatedbyhand(1meconsumingandlabourintensive)

3.  Purifying–metalsaremelteddowntoformblocks

Aluminium Copper Gold IronandSteelUsefulProper9es•  Lowdensity•  Doesnotcorrode

(becauseoflayerofoxidethatformsquickly)

Uses•  Aeroplanesandcars

tomakethemlighter(cheapertorunastheyneedlessfuel)

UsefulProper9es•  Duc1le•  Lowreac1vity(does

notreactwithwater)•  Goodelectrical

conductorUses•  Electricalcables•  Waterpipes

UsefulProper9es•  Veryunreac1ve•  Doesnotcorrode•  Malleable•  Remainsshiny•  Excellentelectrical

conductorUses•  Jewellery•  Electronicdevices

(printedcircuitboardsandconnec1onstrips)

UsefulProper9es•  Cheaptoextractby

hea1ngwithcarbon•  Pureirontooso^but

inalloysisveryuseful•  Steel(Ironmixedwith

carbonandothermetals)isstrongandhard

•  Magne1cUses(mainlyassteel)•  Bridges,cars,cutlery,

electricalgoods,machinery,buildingframes,magne1cproducts

C1.20Proper1esofmetals

KeywordsMalleable–canbehammeredintoshapeConduct–allowsheatorelectricitytopassthroughitDuc9le–canbestretchedintowiresDensity–themassofasubstanceperunitvolume;theunitisusuallyg/cm3

Proper1esinclude:–shinywhenpolished;conductheatandelectricity;malleable;duc1le.

C1.21AlloysKeywordsAlloy–ametalmixedwithsmallamountsofothermetalstoimprovetheirproper1esCarats–ameasureofthepurityofgoldwithpuregoldbeing24caratsFineness–anothermeasureofpurityofgold(partsperthousand)Smartmaterial–amaterialthat’sproper1eschangewithachangeincondi1onsShapeMemoryAlloy–analloythatcanreturntoitsoriginalshapewhenheated

Puremetal1.  Allatomsarethesamesizeandthereforecloselypacked

together.2.  Thismeansthatlayersofatomsslideovereachotherwhich

makesthemetalsoh.3.  Inanalloydifferentatomsareaddedwhichpreventtheatoms

slidingsoeasily=harderandstrongerExamplesofAlloysAlloysteels–ironmixedwithothermetals•  StrongerthatIron•  Someresistcorrosion.StainlesssteelNEVERcorrodes(IronwithChromiumandNickel)Gold-Puregold(24carat)tooso^.24caratgoldhasafinenessof1000partsperthousand•  CopperandsilveraddedtomakeitharderNi9nol–Smartmaterialmadefromnickeland9tanium•  Returntooriginalshapewhenheated.•  Usedinrepairofarteries(insertedinsquashedandcoldandwarmswithbodytoreshape)•  Flexibleglassesframes

Puremetal

C1.22CrudeOil

Keywords•  Hydrocarbonsarecompoundsthatcontaincarbonandhydrogenonly.

•  Crudeoilisacomplexmixtureofhydrocarbons

C1.23CrudeOilFrac1ons

•  Crudeoilisseparatedintosimpler,moreusefulmixturesbyfrac1onaldis1lla1on.

C1.23CrudeOilFrac1ons

Frac9on Uses

Gases Domes1chea1ngandcooking

Petrol Carfuel

Kerosene Aircra^fuel

Dieseloil Fuelforsomecarsandtrains

Fueloil Fuelforshipsandsomepowersta1ons

Bitumen Surfacingroadsandroofs

Thereare6frac1onsyouneedtoknow…

C1.23CrudeOilFrac1ons

Frac9on Lengthofmolecule

Easeofigni9on Boilingpoint Viscosity

Gases Short

Long

Easy

Difficult

Low

High

Runny

Thickands1cky

Petrol

Kerosene

Dieseloil

Fueloil

Bitumen

Keywords:Igni1on–tosetalightViscosity–Howthickorrunnyasubstanceis

Howdothefrac1onsdiffer?

C1.24Combus1on

Keywords:Combus1on–achemicalreac1onwithoxygen(oxida1on)toreleaseenergy.Completecombus1on–whereallthehydrocarbonisusedup.Oxida1on–theaddi1onofoxygen.

+Energyreleased

AnyhydrocarbonTestedforusinglimewater.CO2willturnitcloudyifpresent.

C1.25IncompleteCombus1on

Keywords:•  Incompletecombus1on–wherethereisnotenoughoxygenforthefuelto

completelyburn.•  CarbonMonoxide–poisonousgasproducedduringincompletecombus1on.

Waterisformedjustlikeincompletecombus1onbuttherearenotenoughoxygenatomstoformCO2.SootandCarbonMonoxideareformedinstead.3differentequa1onsshowwhatcanhappen:Methane+OxygenàCarbon(soot)+WaterMethane+OxygenàCarbonMonoxide+WaterMethane+OxygenàCarbonDioxide+CarbonMonoxide+Carbon(soot)+WaterDifferentpercentagesofCO2,COandCareproduceddependingontheamountofoxygenpresent.

C1.25IncompleteCombus1onProblemsofincompletecombus9on:•  CarbonMonoxideisanodourless,colourless,toxicgas.

•  ItreducestheamountofoxygencarriedbytheRedBloodCells.

•  Carbonmonoxidepoisoningcankill.•  Sootcanclogpipescarryingwastegases.•  Faultyorblockedboilerscanproducecarbonmonoxide.

C1.26AcidRainKeyword:Acidrain–rainthatismoreacidicthannormal.Impuri1esinhydrocarbonssuchassulfurreactwithoxygentoproducesulfurdioxide.Thisdissolvesinrainwatertoformacidrain.4ProblemsofAcidRain:•  Rivers,lakesandsoilsbecomeacidicharminglivingorganisms•  Damagestrees•  Speedsupweatheringofbuildingsmadeoflimestoneormarble•  Corrodesmetal

C1.27ClimateChange

3gasestrapheatfromtheSunandkeeptheEarthwarm–GreenhouseEffect•  CarbonDioxide•  Methane•  Watervapour

TheEarthstemperaturevaries.Humanac1vitysuchasburningfossilfuelsmayinfluencethis

C1.27ClimateChange•  Theamountofcarbondioxideintheatmospherevaries

duetohumanac1vity–burningfossilfuels.

Howtoreducetheamountofcarbondioxideintheatmosphere:•  IronSeedingOceans–Addingirontotheoceanencourages

algalgrowthwhichphotosynthesiseandabsorbcarbon.Theyareeatenbyotherorganismswhichincorporatecarbonintotheirshellswhichsinkstothebo>omoftheocean.

•  Conver1ngcarbondioxidebacktohydrocarbons–trappinggasesfrompowersta1onsandreac1ngthemtomakebutaneorpropanetouseasfuels.

C1.27ClimateChangeKeywords:•  Correla1on–apa>ernwhichissimilarintwovariables.Itcouldbeduetochance.•  Causa1on–whenonevariablecausestheeffectintheother.

•  Thereisacorrela1onbetweencarbondioxidelevelsintheatmosphereandtheEarthstemperature.

•  Notallscien1stsareconvincedthatincreasingcarbondioxidelevelscauseglobalwarning.

Because…•  Therearefluctua1onsthroughouthistory•  Thereareothercausesofglobalwarning•  Thereareothergreenhousegases•  Futurepredic1onsarejustpredic1ons

C1.28Biofuels

Keywords:Biofuel–Afuelmadebyhumansfromanimalorplantmaterialthathasrecentlydied.Ethanol–Afuelmadefromsugarbeetorsugarcane.Biodiesel–Dieselmadefromplantmaterial.Carbonneutral–afuelthatdoesnotaddanycarbontotheatmosphereoverall.Biofuelsareapossiblealterna1vetofossilfuelse.g.ethanolwhichcouldreducedemandforpetrol.AdvantagesofBiofuels DisadvantagesofBiofuels

Theyarerenewable Growingcropsforfuelsrequireslandthatcouldbeusedtogrowfood

Plantsremovecarbondioxidefromtheatmosphereastheygrow

Transporta1onofthefuelsproducescarbondioxide

Burningthefuelsproducescarbondioxide

C1.29ChoosingFuels4factorsthatmakeagoodfuel:•  Howeasilyitburns.•  Howmuchashorsmokeitproduces.•  Thecompara1veamountofheatenergyitproduces.•  Howeasyitistostoreandtransport.

•  Afuelcellcombineshydrogenandoxygentomakewaterandreleasesenergy.

•  Petrol,Keroseneanddieseloilarenon-renewablefossilfuelsmadefromcrudeoil.•  Methaneisanon-renewablefossilfuelfromnaturalgas.

Advantagesofusinghydrogenasafuel Disadvantagesofusinghydrogenasafuel

Whenhydrogenburnsnocarbondioxideisproduced,onlywatervapour

Hydrogenusuallyproducedfromnaturalgasandtheprocessreleasescarbondioxide

Hydrogenfuelcellsaremoreefficientthanpetrolengines

Hydrogenneedstobereadilyavailablefirst

Renewable Petrolsta1onswouldhavetobeconvertedtostoreandsellhydrogentoo

Costoftheabove

C1.31AlkanesandAlkenes

Alkanesaresaturatedhydrocarbonswhicharepresentincrudeoil. Learnthe

formulaandbeableto

draweachofthese.

C1.31AlkanesandAlkenes

•  Alkenesareunsaturatedhydrocarbons

Brominewaterisusedtodis1nguishbetweenalkanesandalkenesEthene+brominewateràcolourless(colourless)(orange)Ethane+brominewateràorange(colourless)(orange)

Learntheformulaandbeableto

draweachofthese.

C1.32Cracking

Crackinginvolvesbreakingdownlongsaturatedhydrocarbons(alkanes)intosmallerusefulones.Someofthesesmallmoleculesareunsaturated(alkenes).

Knowhowtocrackparaffininthelab.

Whyiscrackingneeded?Crudeoilhasdifferentamountsofeachfrac1on.Thesedon’talwaysmatchcustomerdemandsotheycrack

themtomatchdemand.

C1.33Polymerisa1on

Manyethanemoleculescancombineinapolymerisa1onreac1on.

Learntheformulaandequa1on

C1.33Polymerisa1on

4examplesofpolymersyouneedtoknow…

C1.33Polymerisa1on

Polymer Proper9es Use

Poly(ethane)–polythene Flexible,cheap,goodinsulator

Plas1cbags,plas1cbo>les,clingfilm,insula1onforelectricalwires

Poly(propene)–polypropene

Flexible,sha>erproof,highso^eningpoint

Bucketsandbowls

Poly(chloroethene)-PVC Tough,cheap,long-las1ng,goodinsulator

Windowframes,gu>ers,pipes,insula1onforelectricalwires

Poly(tetrafluoroethene)PTFEorTeflon

Tough,slippery,resistanttocorrosion,goodinsulator

Nons1ckcoa1ngsforsaucepans,bearingsforskis,containersforcorrosivesubstances,stainproofcoa1ngforcarpets,insula1onforelectricalwires

C1.34ProblemswithPolymers

3problems•  Mostarenotbiodegradable.•  Theypersistinlandfillsites.•  Theyproducetoxicgaseswhenburned.

Howcanweovercometheseproblems?•  Recyclingpolymersinsteadoflandfill.•  Developmentofbiodegradablepolymers.