Note 17 Feb 2024 Chemistry Notes PDF

No. Date. Covalent bonding non metalsonly shared pair of electrons s...

No. Date. Covalent bonding non metalsonly shared pair of electrons simplecovalent ce ce chlorineCla H ce HydrogenchlorideHee H O H Water Hao 0 0 Oxygen Or o c o carbondioxide coz xx H ice C H Y H Cla H ee ce q structural properties strongcovalentbond but theatomsin the molecule areheld togetherbywean intermolecularforces ofattraction MELTINGANDBOILING Points LowMELTING Boningpointsas theweanintermolecular forcesof attractionbetweenmoleculesareeasilyovercomewith a smallamtofenergy SOLUBILITY Mostsimplecovalentareinsolubleinwaterandsolubleinorganicsolvents ELECTRICAL CONDUCTIVITY simplecovalentsubstancestypicallyexistas neutralmoleculestheydonot haveanymobilechangecarrierstoconductelectricity Howeversomesimplecovalentsubstancesdissociatein waterandtheresulting solutioncanconductelectricityAnexampleis hydrogenchloridewhichdissolves inwatertoformH andCe ionswhicharemobile Hence thesolution is an electricalcondur Giant Covalent i alwaysinsolidstatebecausetheyconsistofmanyatomsthatareall tooneanotherbystrongcovalen connected bonds Diamond Graphite Graphene Silicondioxidecsio Results in structuresthatconsists of repeatingunitsof atomstomanewhatareessentially giant molecules manyatomstogether STRUCTURAL PROPERTIES numerousbondsholding makingthemreallyrigidandableto withstandlargeforces strongelectrostaticforcesof attraction nointermolecularforces ofattraction  No. Date. GRAPHITE Strongcovalentbondsarefoundwithineachlayer weakintermolecularforces ofattractionexistbetweenthelayers canbeeasilyseparatedfromelo buteachlayerishardtobreakapart Graphitelayers HARDNESS Diamond is hardas it'sstructureismade upofonlystrongcovalentbonds Alargeamtofenergyisneeded tobreakthestructureapart Graphite is softandslippery only a smallamtofenergy isneededto overcome theweak thelayersof carbonatoms Hence theselayers forcesofattractionbetween intermolecular ofcarbonatomscanslideovereachothereasily canbeusedinsolidlubricant canalsobeusedinwritingsincepressing it onpaperwillshearofflayers ofgraphitleaving ablackmanonthepaper MELTINGANDBOILING POINTS HIGHMELTING Boilingpointsduetothelargeno ofbondsinthenetworkTomelt thesegiantcovalentsubstance a largeamtofenergy isrequiredtobreakthestrong covalentbonds Hence theyaresolidsat notp withveryhighmeltingandboilingpoints SOLUBILITY Mostgiantcovalentsubstancesareinsolubleinwaterandinorganicsolvent ELECTRICALCONDUCTIVITY Giantcovalentstructurewithnomobileelectrons likediamondsandsilicondioxidedo not conductelectricity cation however in graphite eachcarbonatomis bonded to atomsThisleaves I unbonded electron per carbonatomwhich is freeandmobile to conductelectricity Macromolecules a covalentsubstances eg polymers structureProperties Polymersvarygreatlyintheirhardnessandflexibilitybecausethey existin somanydifferentcombinationofatoms strongelectrostaticforcesof attraction weauintermolecularforces of attraction MELTINGANDBOILING POINTS Polymermaybeformed bymoleculesof a rangeofsizes Thus polymers donothave afixedmelting boilingpoint Instead theytypicallysoftenover a range oftemperatureswhenthe weakerintermolecularforcesofattraction are overcomebythemolecularvibrationswith higherkineticenergy polyethene is a polymerwithweau 1MF betweenmolecules Hencem pandbp ofpolyethene islow SOLUBILITY mostmacromoleculesareinsoluble inwaterandsolubleinorganicsolvent ELECTRICALCONDUCTIVITY mostmacromoleculesarenotabletoconductelectricity in anystatesastheydonothave mobileions electrons  No. Date. Ionic Bonding metalandnon metals strongelectrostaticattraction betweenpositiveandnegativeions Giantionic lattice calciumchloride cace hi magnesiumoxide Mgo aluminiumbromide as MELTINGANDBOILINGPOINTS duetothestrongelectrostaticforcesofforces betweentheoppositelychanged ion Ionsarearranged ina LATTICEof repeatingunits ofpositiveandnegativeIons HARDNESS Theseform a crystal ioniccompoundishard astheattractiveforcescausetheionstoresistmotion 00 00 whenenoughforce isapplied theionsmoveawayfromtheirlatticeand q ionswiththesamechangeapproach elo Therepulsiveforcesbetweenionsofthe samechangebecomelargerthanattractiveforces andthelatticestructureshatters Positiveions Hence ioniccompounds arehandbutbrittle ex are knownas cations whilenegativeionsc s arecalledAnions Ioniccompoundsare also It Idiotic diet thenMorten insolution dissolved called salt eg sodiumchloride Thisisbecausetheions arefreetomoveinthesestates andtheycanny charge Insolidstate theionsinthelatticeareonlyabletovibrate abouttheir fixedpositionHencetheionsarenotmobile SOLUBILITY Mostioniccompoundsaresolubleinwaterandinsolublein organicsolvent whenioniccompound aredissolved inwater wesaythattheyare inthe aaeousstate Metallic Bonding metalsonly strongelectrostaticattractionbetweenpositiveionsandnegative delocalisedelectrons ion intositive e e delocalisedelectrons I tie't tai's t loseelectrons to formpositiveionsanddelocalisedelectrons Giant metalliclattic um my III Aluminium Al Na Analloy is amixtureofmetal with 1 or moreotherelements Structural properties ifenoughforceisapplied thelayers ofatomscanslideover oneanothereasily Hencewhenhammered puremetalscanbebent or flattenedinto athinsheetmalleablethey canalsobepulledinto a wirew obreakingcauctile the seaofdelocalisedelectrons willcontinue toholdthemetalionstogetherunless a much greaterforce isapplied  No. Date. Inan alloy theatomsareofdifferentsizesTheregularlattice inthepuremetal is distrupted so a largerforceisneeded arrangement tomanethelayersslideovereachotherAs aresult alloystendtobelessmalleableand lessductilethanpuremetal Anoysare harderandstrongerthanpuremetals strongelectrostaticforces of attraction MELTINGANDBOILING POINTS HIGHMELTING Boilingpointbecausetheatomsareheldtogether heldtogetherin alatticebystrongmetallicbonds Becausealloysare a rangeoftemperatures mixture uninepuremetalswhichha metalsandalloysaregood conductors of heat asthedelocalised valenceelectronsallow efficienttransferofthermalenergythroughoutthegiantmetalliclattice ELECTRICALCONDUCTIVITY the seaof delocalised electrons foundinbothmetals alloys makethemgoodelectricalconductors simplemolecular structure egHao coz 02 Strong covalentbondbetweenatoms weakintermolecularforcesof attractionbetweenmolecules soft insoluble inH2o soluble in organicsolvent poorconductivity lowboiling point Giantcovalentstructure strong efa noIMF hardexceptgraphite as onlylittleenergy is neededto overcomethe weakIMF insolvablein both poorconductivity exceptforgraphite No. Date.  No. Date. MOLES RELATIVE ATOMIC MASS molesareused to compare quantities ofsubstance 1MOLE 6.02 10 atoms molecules 12g ofcarbon I mole eg Howmanymoles is 96gofoxygen I formulamass of 02 2 16 32 t.ge g mon 3m01 iii iii iii iiiiiiiiiii PERCENTAGE MASS formulaxAnoftheelement numberoftheelementinthe Percentage mass Mrof compound Example question Findthepercentagemassofnitrogeninammoniumsulfate chital soy Relativeformulamassof Nita son 44 32 41161 Percentagemassofnitrogen incNH4 so 14,5 100010 21.2010 Using MOLES unitweusetomeasuretheamtof chemicalwehave 1more of anysubstance 6.02 10 Particles Avogadro'sconstant 9 m eg I mole of oxygeh atom 6.02 10 oxygen molecules oxygen gascontain 120 1024 E.gl mole ofsodiumchloride contains 6.02 1023sodiumionsand 6.02 1023chlorideions mn nsotana z fffIadem ti s 449 iii 44 Formula Theno ofmoles 98m hyglement in a sample Mr Avogado'sconstant n s Howmanymoles in 42.5g of ammonia no No ofmoles 42,5 2.5molesofAmmonia What isthemassof Moles ofcarbondioxide Molarmass mn moles 3 12 10 2 132g ofco No ofmoles Mm mass Themass of a Particularelementwithin a largercompound massof carbon in 31401ofCoa 3 12 36g  No. Date. 36g Example question Howmanygrams ofwaterwouldbemade ifbag ofmethanereatedcompletelywithoxygen 202 Massofsubstance molesof caso a substance MOLES MASS ccity 64g moles 4 2 8mot 18 8 144g Grams 4mole rains xmores yams Example questions calculatethemass ingrams of 4.5 moles of lead II soul sulfateCpb Molan mas of Pbso in g moi 207 32 4016 303g moi mass of Pbsoy in g no of moles of Pbsoy x molarmass ofPbso in g mol 4.5 303 Boog MOLESANDGASEOUSVOLUME Imoleof anygasoccupies a volumeof24dm at roomtemperatureandpressure no ofmolesofgas volofgasinam 24dm 60dm of o howmanymoles a moi ExampleQuestion calculate voloccupied by a moles of oxygen gas volume of oz in dm no of moles x 24dm 2 24 48dm CONCENTRATION OF A SOLUTION antof asolutedissolved in aunitvolumeofthesolvent am le mass ofsoluteing Concentration in glam volumeofsolvent indm M e v Example question A 500cm solutionwasmadebydissolving 2 moles of sodiumchloridesnare inwater Findthe concentration of the sodiumchloridesolution in g dm Molarmass of Mace in gimoi 25 35.5 concentration of Macein g dm 177 sq sg.gg mo 234g dm Mass of maceing 2 58.5 117g  No. Date. CONCENTRATION IN moi dm no ofmoleofsolute concentration in moi am volumeofsolventinam Examplequestion A zooam bydissolving ltugofpotassiumsulfatecuzsoy inwaterFindtheconcentrationofthepotassiumsulfate solutionwasmade solution in moi dm Molarmassof u son in g moi zeal satcaxio 174g mol 74 Numberofmolesof uso 174 o.o moi concentration of u soy in moidm3 0.01 30 0.5moi dm volume number ofparticle gram am number 240am numberof molarmass ofme catnap of number go mores in mo g mm massing of number moles volume of concentrationvolume concentration in solvent inmonamsolutionin ingram am am  No. Date. Stoichiometry calculate no of mole of C3H4 No of moles of C3Hg 0 I mol Algorithmic expression I mol of Colts reacts with 5 mol of 02 0.1mol of Colts reacts with 0.5mol of 02 Mass 0.5 32 16.09 Empirical and MolecularFormula thesimplestratio ofelement inthe compound Mr of empirical formula is factor of mn of molecularformula a C H 0 Mass g 40.0 6.7 53.3 Number of molesmol 3333 67 6.7 52 3.33125 Moleratio I III I 2 1 Empirical formula is CH20 Mnofmolecular formula n mnof empiricalformula 60 n 1242416 60 nc30 i n 2 Molecular formula is 2H40 0.5 0.25 0.333 DONTROUNDOFF C H 0 x2 4 3 massin1009 64.6 108 24.6 sample g No ofmoles 64 5.383 148 10.848 1.537 mol moleratio 5 43 3.5 7 1 simplestwhole 7 14 2 no ratio  No. Date. formolecules inozmolofcoz Asking 0.2 6.02 1023 1.20 10 molecules A suingforatomsin1.5molesofLiality 1.5 6atoms 6.02 1023 5.42 1024atoms Askingforionsin3.3 molesof mg 3.3 3 6.02 1023 5.961024ions Noofmoles 6 14 3 1 mol 6.02 1023 Askingforno ofatoms in 1.00molofF 2 6.02 1023 1.20 1024 Caison Asuington the volume of monoxide Mr 1216 no m.es Izsmol volume of co 0.125 24 3.00dm Asking for no of moles of 18.0dm of Nz 18.0 24 0.750mo Askingforconcentration in mollam 9.80g of itso in250cm ofsolution concentration ingrams 28 8 39.2gdm Mr 2 32 104 98.0 concentrationinmol 1dm 38 0.400mmdm  No. Date. TITRATION a lameaccurate initialreadingem Volumeof Pasedcm Best titrationresults Avérig volume of p required finalanswercza.pl ViiimÉ ofsolution Q used was finalanswerisaps initial fffya.infqf Accuratevolume I I S Element a substance containingonly Itype of atom eg Mg 02 compound a substance containing 2 or moredifferenttypes of atom CHEMICALLYBONDED eg Hao Chu 202 CO2 2H20 MIXTURES ANDSEPARATION TECHNIQUES hate Filtration removeslargeinsolubleparticlesfroma liquide Evaporation leavesbehindcrystals of a dissolvedsubstance solute if heated gently evaporatingbasin PHYSICAL Distillation involvescodensingtheevaporatedsolventandcollecting it nonewsubstan ff ff jsffff.fi aremade  No. Date. PURESUBTANCE PuresubstancehaveveryspecificMELTINTING Boilingpoints whichcanbeusedto testfor them CHROMATOGRAPHY theseparatingofa mixturetoidentify its constituent substances eg pigments in inu The Mobile PHASE solvent water movesup the filterpaperdue to CAPILLARYACTION TheRt valuescan thenbecompared Rtvalue did mb nma ed STATES OF MATTER EnergyHEAT is needed to 888 overcome the electrostatic forcesofattraction between particles to melt evaporate yement arefarapartmoverandomly atfastspeeds highenergy particles ATOMIC STRUCTURE hiII ATOMICANDMASSNUMBERS hate nucleus ISTOPES sameelement diffnumberofneutrons carbon is has7 neutrons somemass numbers onperiodictablearenotunder theseare an AVERAGEmassof all isotopes name chlorine 37 is25 averagemass totalmassof.noatoms ELECTRON CONFIGURATION 135 75,4 7 25 Forexample 35.5 magnesium mg has 12electrons intotal so its electron configurationmustbe 2.8.2 METALS NON METALS METALSalways DONATEelectrons togainan EMPTYOUTERSHELLtoformPositiveionceg Nat  No. Date. ASalwaysACCEPTelectrons to gain a FULLOUTERSHELL NON MET TheycanformNEGATIVEions eg0 canshareelectrons todothis GROUP Numberof electrons in outershell Group I aretheALKALIMETAS Group7 are the HALOGENS astheyreactwithwater toproduce analkali They form a ions asthey Theyalllose donatetheir outerelectron so accept I electron togainfullouter theirions are all 11 eg Nat shell Theygetlessreactivedownthe group and boilingpoint increases Theygetmorereactivedownthegrp as theouter electron is furtherfromthe ÉÉ di theforceof attraction isless IIff TheNOBLEGASESgroup0 8 areVERYUNREACTIVE astheyalready haveanempty fulloutershell NEUTRALISATION MAKINGSALTS I I ACID CARBONATE SALT water coz eg zice cacos cacle Hao cos Igte it  No. Date. RelativeAtomic Mass Average mass of one atomof that element compared to mass ofcarbon12ato Relative MolecularMass Mn Averagemassof 1moleculeof a covalentsubstancecompared to themass of carbon 12 atoms Mole Avogadro'snumber 6 1023 mass no ofparticle y holan Avogadro's number mass noni no How 1 2 mol of H2O manyHatomsarethenin 1 0.5mol ofHce Mass 2 18 no of atoms 0.5 6 1023 36g 2 I mol ofHao 2 6g of carbon NHzo 1 6 10 no ofmole 6 10 H2O molecules no 1 NH 2 6 1023 I mole occupies 24dm 3 0 mol of NHz volume NH 3 6 1023 n Um molarvolume 24dm no ofmole is0.25moldm That Interact.in enfnaiiosnutfficae idinsoji I concentration 0.25 1 2 32716 4 0.25 98 24.5g1dm No. Date.  No. Date. Acids Bases Acid Metal salt He Acid Bases Salt H2o neutralisation Acid Carbonate Salt Coz H2o Propertyof Acids Physical chemical sourtaste Reacts w reactivemetal toformsalt Ha exept Cu Ag Electrolytes Reacts w base toformsalt Hao neutralisation pHbelow 7 Reacts w carbonateto formsalt H2o Co2 Acid Acid is a substance thationises to formhydrogenions H whendissolvedinwater similaritiesbetween weauacids strongacids Bothionised in H2o Turnbluelitmuspaperred Reactswithreactivemetals metalcarbonate bases Conductselectricity Differences Extentofionisation strongacidcompletelyionised Weak acid partially In ionised Arrowin equation Strongacid weakacid I strong acid I to 3 weakacid 3 to 7 Basicity of Acids Acids are classified as monobasic dibasic ortribasicdependingon the number of itatomsin a molecule thatareable to formH ionswhen it ionises in water  No. Date. Oxides Oxides Metal Yxides Nonmetal oxides at are ten iii basic 7103 areacidic reacts w teact can acids w Bothacidt willnotreact ua bases withacids bases Strength vs concentration Strength theextent of ionisation of an acid alkali cannot be controlled concentration the amount of an acid alkali dissolved in solution Definestrongacid is one thationisescompletely whendissolved in water to form H ions Higher the bond energy the weaker the acid is A larger bondenergy means the bond is hederthovercome Hence it's harder forcompound toionisen  No. Date. Hce is able to produce 1 Htions permoleculewhen ionised in H2o monobasic Hcecaa H caq Ce caa Hasonsulfuricacid is a dibasic as each moleculeproduces 2H ions in H2o Caa Hason 2H 5042 caa HsPon phosphoric acid is tribasic as itproduces3H ionspermolecule in water H3Po4 43caa 3Hcan PO Not all Hydrogen atomsin anacidmolecule form H ions ethanoieacid CH00Hcaa Atcaa coCoo Caa compare o.comol dm Heeand 0.100moldm He504 which willhave a higherconcentration of H ions Sulfuricacidhas a higherconcentration of H ions Bothacidshavethesameconcentration strength However their basicity is different sulfuricacid is a dibasicacid so it willproduce 0200m011dm ofH ions Hee is a monobasicacid so it willproduce 0.100not1dm ofH ions Bases Difference betweenAlkali and Base Alkali substance that dissociatestoformhydroxideions0H whendissolved inHzo Base substance that reacts withacidto formsaltandH2O hydroxide metaloxide Acid Base salt Haoce Amati Ammonium salt ioniccompound ff.fiaIfiifa Basesthat's insoluble copper II oxide iron II hydroxide soluble oxide SPA Bases that'sson soluble0H S weau Éninglysoluble NaOH NH Properties ofAlualiI Bitten Electroiytes turnred litmuspaperblue slippery soapy  No. Date. w.it i ia.ii.i.iiiniiiiii.aniumn ii aiiimioniumnit.at at thesame time Caloit12Caa 2MtNocaal cacrossa caa 2H20 e Nitcg calcium hydroxide reacts withammonium nitrate releasing Ammoniumgas thisresulting in a loss ofnitrogeninthesoil How Do we compare Acidityand Aluality universalindicator Methylorange Acidicsolution red Alkalinesolution yellow Screenedmethyl orange solution red Alkalinesolution blue in colourless Alkalinesolution blue PH 7 ofH ions is higherthanOH ions concentration pH 7 concentration of H ions OH ions pH 7 concentration ofH ions is lowerthanOH ions  No. Date. CalculationofpH measuresconcentrationofH ionsinsolution pH eg At not1dm not1dm calculatethepH of0.0100mollam Heeand0.00500 Hzsoy pit of0.0100mollam ofHee egcool 2.00 pH of 0.00500mmol1dm Hasoy lg 2 0.0051 2.00 A Haso is a dibasicacid Solution has a pHof 1and Y has photz calculate Ht inbothsolutions Ht in X 10 0.100moldm 2 H in Y 10 0.0100not1dm Salts anioniccompound formedbythereplacement of 1 1 morehydrogenionsofanacid by a metallicion ammoniumion solubilityofsaltsinH2o All sodium potassium ammoniumsaltand nitrate SPA NO Allchloridesexcept silverchloridecagce andlead II chloride Pbcea SL Allsulfates except barium lead II calciumsulfate sparinglysoluble CBL soluble Allcarbonateexcept sodium potassium ammonium zinccarbonate SPA Solubility ofmetaloxidesandhydroxides note theyareNOTsalts AllmetaloxidesandhydroxidesareinsolubleexceptGroupI metaloxides Group2 elements ca snandBalincreasesolubilityfromca onwards MgoandMycottleareinsoluble Cao andCacoma are sparinglysoluble Sno and srCOHlz are soluble Baoand Bacon are soluble  No. Date. How are saltsprepared IfsaltissolubleinH2o byreactionsofacids Ifsalt isinsolubleinH2o byprecipitation : Method 1 reactionof acid with insoluble substance coppercal sutate ca Hasoy toounreactive step1 Determine if salt is soluble inH2o salt solublein H2o zincsulfate is soluble calciumnitrate ca No explosive Step2 identifythe starting materials 2n504 possiblematerials sulfuricacid zincmetal in de zinc P Step3 determine ifthestartingmaterialsaresolubleinH2o zincsulfate soluble in H2O zincmetal zincoxide and zinccarbonate are insoluble inH2O method I can beused step3 selectstartingmaterials Sulfuricacid zinemetal dilutedsulfuricacid zinc zincsulfate hydrogen Hz soycoal Zn s 2n504Caa Hecg Method 2 Titration Bothneed to be soluble general equation Acid Alkali Salt water Acid solublecarbonate solublesalt water can ToprepareSPA sodium potassiumand ammonium makeall hydroxide Sodium hydroxide Step1 determine if saltis soluble inH2o Potassium hydroxide AqueousAmmonium Step2 decidestartingmaterials NaN 03 Nitricacid Sodiumhydroxide sodiumcarbonate Step3 determine if starting materials are solubleinH2o  No. Date. Step 4 selectstartingmaterials Method 3 Precipitation for insolublesalts generalequation solutionABcaq solution Ycaa AY insolublesalt solution Bcaq if norestrictionalways choosesodium nitrate step 1 determine if saltissolublein H2o Bariumsulfate Basox carbolic acid step2 identifythesuitablemethod startingmaterials worustoo Sulfuricacid Barium nitrate Question whycan'tcalcium sulfate be used it is insoluble in H2O willnotdissociate to provideanysulfateions in solution There will notbeany Bason formed MCQAssignment Q1 which of followingdoesnot givegoodyield ofsaltwithdilutesulfuric acid Ironcalhydroxide soluble sodiumhydroxide highlysoluble zinc hydroxide soluble leadcal hydroxide formleadoil sulfatewhich is insoluble Q3 Bad 0312Caa Alacson caal Basoyest Al Nos 3 equation aq aq s Qa canaddingexcess magnesium chlorideto nitricproducemagnesiumnitrate No Asmagnesium chloride is already a salt andaddingnitricacid no reaction will happen Topical revision package MCQ QI whatwillbethepHHceafter adding logofsodiumchloride sodiumchloride neutral AddingNacedoes not change H ion concentration so pHremainsthesame Q3 How would thepH of solutionchange as HCl is added to NaOH till no change It decreases from pH14 to pH1 and remains constant  No. Date. Q6 Acid M is mixedwith solid N Thefinalmass ofmixtureislessthaninitialmass choose the onethat produces gas as theloss in mass isduetotheformation of gasduringtheprocess Q8will addingdilutesulfuric Hzsoy to calciumcarbonatecaco producethebestyield of casoy No as adding Hasoy to cacos will cause casou to form a insolublecoating around cacos Thereaction willstopas thecasoycoating willpreventcacosto reactwithdiluteHasoy The reaction willthenstopBY it's completed Summary When salt is soluble Method 1 Reactionofacid withinsolublesolution When salt is soluble andappears to beSPA sodium Potassium Ammonium Method 2 Titration MUSTBE acid alkalireaction acid carbonatereaction Bothreactantsneed to be soluble when salt is insoluble Method3 Precipitation Bothmaterialsneed to be aq Acid Basereaction Base hydroxide oxide Acid Base salt H2o No. Date.  No. Date. precipitateformed withNaOH or Nits are metalhydroxides NaOH NHS on iii NH wornas NH H2o NH4t OH common question writetheionicequation ofpptformed 1ststep Fecott s writeout product 2ndstep Fe caa 20H caq Fe10H12 s remember 100010 in aa state an aa s How to test for ammonium ByaddingNaOH produceNH gas onheating  No. Date. bubbles B. ate HMO I  No. Date. Caco Calott z onlyreflect2colours red blue Imelly I willdissapear Purple NHgascandissolve toproduceOHion