chem notes 'N'

Rebekah’sChistryNotes CONTENTPAGE: 1.Importantskills:chemicalformulaeandequations----------------------------2-7 2.Experimentalchemistry—---------------------------------------------------------8-20 3.KineticParticleTheory------------------------------------------------------------21-25 4.Atomicstructure--------------------------------------------------------------------26-29 5.Chemicalbondingandstructurepropertiesofmaterials-----------------30-37 6.Themoleconceptandstoichiometry------------------------------------------38-40 7.Acidsandbases--------------------------------------------------------------------41-48 8.Maintainingairquality-------------------------------------------------------------49-52 9.Theperiodictable------------------------------------------------------------------53-56 10.Thereactivityseries-------------------------------------------------------------57-62 11.Fuelsandcrudeoils-------------------------------------------------------------63-77 1

IMPORTANTSKILLS:CHEMICALFORMULAEANDEQUATIONS SkillA:DEDUCINGCHEMICALFORMULAE 1.Determiningvalencyofelements ValencyfromGroupnumbers: -towritethechemicalformulaofacompound,wemustknowthevalencyof theelementsorpolyatomicionsinvolved -valencyfromgroupnumberintheperiodictable Groupnumberin theperiodictable ExampleofelementValency 1 Li,Na 1 2 Be,Mg 2 13 B,Al 3 14 C,Si 4 15 N,P 5 16 O,S 6 17 F,Cl,Br,I 7 ValencyfromRomanNumerals -transitionmetallicelementshavevariablevalencies. -therefore,theirvalenciesareindicatedbyaRomannumeralinthebracket Romannumeralvalency copper(ll) 2 Iron(lll) 3 lead(lV) 4 Manganese(Vl)6 2

ValencyofPolyatomicIons -thereareradicalswhichconsistofagroupofatomsaspolyatomicions Commonpolyatomicions PositiveValencyNegativeValency Ammoniumion ,NH₄⁺ 1 Nitrateion,NO₃⁻1 Hydroxide ion,OH⁻ 1 Carbonate ion,CO₃²⁻ 2 Sulfateion,SO₄²⁻2 Phosphate ion,PO₄³⁻ 3 Methodstodeducechemicalformulas 1.writetherespectivevalencyandcriss-cross 2.ifthevalencyisequal,noneedtocriss-cross,justwriteouttheformula 3.ifanumberusrequiredforpolyatomicions,abracketmustbeused 4.reducetheratiobyacommonfactorifpossible 3

2.Namingchemicalsubstances NamingIonicCompound -whennaminganioniccompoundcontainingtwoelements: —metallicelementcomesbeforenon-metallicelement —non-metallicelementsendwith‘ide’ ElementsinanioniccompoundChemicalname Calcium,chlorine Calciumchloride (metal)(non-metal) Iodine,lithium Lithiumiodide (metal)(non-metal) Magnesium,oxygen Magnesiumoxide (metal)(non-metal) Sulfur,potassium Potassiumsulfide (metal)(non-metal) -inanioniccompoundwhichcontainsatransitionmetal,aRomannumeral inabracketisgenerallyassignedtoindicateitsvalency -Eg: —iron(ll)oxideandiron(lll)oxide —copper(l)oxideandcopper(ll)oxide —lead(ll)oxideandlead(lV)oxide -polyatomicionwillnotchangeitsnameaftercombiningwithother elements -Eg: —sodiumcarbonate —potassiumsulfate Namingcovalentcompound Whennamingacovalentcompound: -thefirstelementnameremainsunchanged -thesecondelementnameendswith‘ide’ -ifnecessaryaprefixisusedforthesecondelementwhichdependsonthe numberofatomsinvolved 4

NumberofatomsPrefixexamples 1 monoCarbonmonoxide(CO) 2 di Carbondioxide(CO₂) 3 tri Sulfurtrioxide(SO₃) 4 tetraCarbontetrachloride(CCl₄) -certaincovalentcompoundhave‘special’names -Eg: —Ammonia:NH₃ —Water:H₂O SKILLB.Balancingchemicalequations Conservationofatomsinachemicalreaction -atomscanneitherbedestroyednorcreated -inachemicalreaction 𝑡ℎ𝑒 𝑠𝑢𝑚 𝑜𝑓 𝑎𝑡𝑜𝑚𝑠 𝑏𝑒𝑓𝑜𝑟𝑒 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛=𝑡ℎ𝑒 𝑠𝑢𝑚 𝑜𝑓 𝑎𝑡𝑜𝑚𝑠 𝑎𝑓𝑡𝑒𝑟 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 5

SkillC:WRITINGABALANCEDEQUATION -statesymbolsaresometimesrequiredifquestiondemandsforit -Eg: —solidstate(s) —liquidstate(l) —gaseousstate(g) —aqueoussolution(aq) Anatomyofachemicalequation: -reactantsareontheleftandproductsareontheright Eg:2HCl+MgMgCl₂+H₂→ Conversionofwordequationtochemicalequation Eg: Inaprecipitationreaction,sodiumhydroxidesolutionismixedwithiron(ll) chloridesolution.sodiumchloridesolutionandinsolubleiron(ll)hydroxide areproduced.writeachemicalbalancedchemicalequationincludingthe statesymbols Step1:identifyreactantsandproductsandplacetheminawordequation. Sodiumhydroxide+iron(ll)chloridesodiumchloride+iron(ll)hydroxide→ Step2:applyskillA,convertthechemicalnamesintochemical formulas.placethembasedontheanatomyofachemicalequationand writethestatesymbolsifnecessary. NaOH(aq)+FeCl₂(aq)NaCl(aq)+Fe(OH)₂(s) → Step3:usingskillB,balancethechemicalequation 2NaOh(aq)+FeCl₂(aq)2NaCl(aq)+Fe(OH)₂(s)→ Writingabalancedionicequation -towriteanionicequation,statesymbolsofthesubstancesmustbeclearly indicated Typesofionicequation: (a)solubilityofsubstancesinwater 6

Step1:SPLITTINGOFIONS -onlyioniccompoundswhicharesolubleinwater(formingaqueous solution)willdissociateintoionsinwater.insolublesubstancecannot dissociateintoionsinwater Eg:NaCl(aq)Na⁺(aq)+Cl⁻(aq)→ Step2:CANCELLINGOUTSPECTATORIONS -spectatorionsareionsthatremainthesameintheiroriginalstatesbefore andafterachemicalreaction Eg:NaCl(aq)+AgNO₃(aq)AgCl(s)+NaNO₃(aq)→ =Na⁺(aq)+Cl⁻(aq)+Ag⁺(aq)+NO₃⁻(aq)AgCl(s)+Na⁺(aq)+NO₃⁻(aq)→ Step3:WRITINGABALANCEDIONICEQUATION Ag⁺(aq)+Cl⁻(aq)AgCl(s)→ (b)changeinoxidationstates -inredoxreactionsuchaselectrolysis,elementsgainorloseelectrons -Eg: —copperatomslose2electronstoformcopper(ll)ions —ionichalfequation: Cu(s)→Cu²⁺(aq)+2e⁻ IMPORTANTCHEMICALFORMULASTOMEMORISE 7

CHAPTER1:EXPERIMENTALCHEMISTRY Quantity measured SIunitUnitscommonly usedbyinstruments instruments /apparatus Accuracy mass kilogram(kg)kilogram(kg) gram(g) Electronicbalance, Beambalance Dependingon instrument (accuracyto2or3 dp) VolumeCubicmetre(m³)Cubicmetre(m³): Cubiccm(cm³) Cubicdm(dm³) Forliquids MeasuringcylinderMeasuresthe cylindertothe nearestcm³ Pipette Measuresthe volumeevery accurately (eg.20.0cm³,25.0cm ³) burette Measuresthe volumevery accuratelyto nearest0.1cm³(eg 26.70cm³,26.75cm³) Forgases GassyringeDependingon instrument (accuracyto2or3 dp) TemperatureKelvin(K)kelvin(K) DegreeCelsius(℃) Thermometer Temperaturesensor attachedtodata logger Accuracytonearest 0.5℃ Time second(s)second(s): minute(min) hour(h) Electronic stopwatch Dependingon instrument(accuracy to2or3dp) 8

Collectionofgas: physicalpropertiesofagasthatwilldetermineitsmethodofcollectionis: 1.solubilityofgasinwater 2.densityofthegas Methodsofcollection: -displacementofAIR -displacementofWATER -gassyringes Upwarddisplacement ofAIR Downward displacementofAIR Displacementofwater Usedwhengasis denserthanair Usedwhengasisless densethanair Usedwhengasis insolubleorSLIGHTLY solubleinwater EG:chlorine,hydrogen chlorideandsulfur dioxide EG:ammonia EG:hydrogen,oxygen andcarbondioxide -ifthegasissolubleinwater,itwilldissolveinwaterandthus,cannotbe collected.hence,displacementofwatercannotbeusedforcollectinggas. 9

-forthegastodisplaceairbydownwarddelivery,gashastobedenserthan airsothatitwillsinkandtakeovertheplaceofair. -forthegastodisplaceairbyupwarddelivery,gashastobelessdense thantheairsothatitwillriseandtakeovertheplaceofthedenseair PHYSICALMETHODSOFSEPARATION: -whentwoormoresubstancesarepresentwhicharenotchemicallyjoined together,itiscalledamixture -amixtureisnotapuresubstance,therearephysicalmethodswhichcan beusedtoseparateamixturetoobtaintherespectivepuresubstances again -aphysicalmethodisawayofseparatingonesubstancefromtheother withoutchangingthechemicalcompositionofthesesubstances -thechoiceforselectingasuitablephysicalmethodisdeterminedbythe physicalpropertiesofsubstancesinamixture Natureof mixture Physical methods Physical propertiesof substances Exampleof mixture solid-solid-magnetic attraction -sieving -usingsuitable solvents -particlesize -magnetic properties -ironfillingsand sulfurpowder -finesaltand sand solid-liquid-filtration -evaporationto dryness -crystallisation -simple distillation -particlesize -solubility -meltingpoint andboilingpoint -saltsolutionand chalkpowder -saltsolution -sugarsolution -seawater Liquid-liquid-chromatography -fractional distillation -solubility -boilingpoint -fooddyes -alcoholic solution -crudeoil 10