Chemistry extra credit PDF

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1 Cec i l i aHei nek e Chapt er1 I nc hapt eronewear ei nt r oduc edt oc hemi s t r y .Wear es hownhowc hemi s t r y r el at est ot her eal wor l dandi snotj us tmadef ort hec l as s r oom.Sc i ent i s t sar enott he onl yonest ous ec hemi st r y .Al ongwi t hs c i ent i s t s ,ot herpr of es s i onsl i k edoct or s ,l awy er s , bus i nes speopl e,fir efi ght er sandmanyot her sus ec hemi s t r y .Chemi s t r ymak est he wor l dar ounduseas i ert ounder s t andandwhatwedowi t ht hi sk nowl edgemak esal lt he di ffer enc e.Chemi s t r ycanbeus edf orgoodorbad.Somei gnor antandgr eedypeopl e usei tonl yt oadv anc eands at i s f yt hems el v es .Oneoft hebadt hi ngsi thasbeenus ed f ori st heenvi r onment al damage.Whenus i ngc hemi st r yi nt her eal wor l dwemustt hi nk aboutt heshor tandl ongt er m affect st oens ur es t abi l i t y . Chemi s t r yi st hes c i encet hatdealwi t hmat er i al soft heuni ver s eandt hec hanges t hesemat er i al sunder go.Thi sc anbes omet hi ngassi mpl easex ami ni ngt i nypar t i c l esor i nv ent i ngnewmet hodst ot r eatdi s eas es .Tos ol v epr obl emsi nc hemi s t r yweus et he s c i ent i fi cmet hod.Fi r s t ,wemus ts t at et hepr obl em,s econdf or mul at eahy pot hesi s ,t hi r d pr ef or m anex per i ment ,andf our t h( i fnec es s ar y )pr ef or mt heex per i mentas ec ondt i me. Thr ought hes c i ent i ficmet hodwehav ec r eat edt hi ngsc al l edt heor i esandl aws .Theor i es ar eanex pl anat i onofanas pec toft henat ur alwor l dt hatcanber epeat edl yt es t edand v er i fi ed.Lawsar et hedesc r i pt i onofanobs er v edphenomenon. Chemi s t r yhasar eput at i onf orbei ngex t r emel yhar d,butt hi si snott r uei fy ou t ak et het i meandgi v ei ty oural l .Oneoft hemos ti mpor t antt hi ngsi st omemor i z et he v oc abul ar y .Al t houghy oumus tk nowt hedi ffer enc ebet weenunder s t andi ngand

2 memor i z i ng.T ot hr i v ei nac hemi s t r yc l assands uc ceedf ur t heraper s onneedst o under s t andandnotj us tk nowf act s . Chapt er2 I nc hapt ert wowel ear nt hedi ffer entt y pesofdat a/ obs er v at i ons .Theyar e qual i t at i v eandquant i t at i v e.Qual i t at i vear eobs er v at i onsaboutt hec har ac t er i s t i csof whati sbei ngques t i oned.Forex ampl e,s ay i ngwhatc ol orofl i ghti semi t t edwhen heat i ngmagnes i um.Quant i t at i v eobs er v at i onsar emeas ur ement s .Measur ement shav e t wopar t s .Thefir s tpar ti st henumberandt hens ec ondpar ti st heuni t .Uni t st el lus whi chs c al ei sbei ngus edt or epr es entt henumber .Ther ear ev ar i ousmeas ur i ng s y st emsus edac r os st hewor l d.Themos tc ommonar et heEngl i s hs y s t em ( usedi nt he US)andt hemet r i cs y s t em ( us edi nmos toft hei ndus t r i al wor l d) .Anot hermeas ur i ng s y st em wasmadebas edofft hemet r i cs y s t em i n1960,t i t l edt heI nt er nat i onalSy s t em. Si nc et hemeas ur ement si nsc i enc ec anei t herbev er yl ar georv er ys mal l ,t hemet hod ofs c i ent i fi cnot at i onwasc r eat ed.Forex ampl e,t henumber5, 462c anbewr i t t enas5. 5 x10^ 3.Anot herex ampl ei st henumber0. 000486c anbewr i t t enas4. 9x10^4.Some meas ur ement sc an’ tbec er t ai nbecaus ei ns t eadofc ount i ngt hems el v es ,s c i ent i s t sus e dev i cess uc hasbal anceandr ul er s .I nt heses i t uat i ons ,t heyt omak eeduc at edgues s es bas edonaddi t i onal t hi nk i ng.Forex ampl e,i far ul eronl ymeas ur est ot hehundr edt hs t hent hesc i ent i s twi l l mak eaneducat edgues sf ort het hous andt hsmeasur ement .Thi s i swher es i gni fic antfigur esar ei mpor t ant .Si gni fic antfi gur ess i gni f yt hedegr eeof c er t ai nt yf orpar t i c ul armeas ur ement s .Ther ul esf orc ount i ngs i gni fi c antfigur esar et hat l eadi ngz er osar enev ers i gni fi cant ,z er ost hatf al l bet weennonz er onumber sar eal way s s i gni fi cant ,andi ft her ei sadec i mal poi ntt het r ai l i ngz er osar eal way ssi gni fi c ant .

3 Roundi ngofnumber si sal s ov er yi mpor t antt or emember .Tok eept henumberof s i gni fi cantfigur esconsi s t entwi t ht hepr obl em andans wer ,r oundupwhent henumber bei ngc utoffi sabov e5ands t ayt hes amewhent henumberc utoffi sbel ow5.Al s o s i ncewehav es omanydi ffer entuni ts y s t ems ,i ti si mpor t antt ok nowhowt oconv er t .To c onv er tf r om oneuni tt oanot heraper s ondi v i desbyt heor i gi nal uni tandmul t i pl i esby t henewuni t . Chapt er3 The“ s t uff” / mat er i al st hatoc c upys pac ei nt hewor l di scal l edmat t er .Mat t erhas mas s .Ther ear et hr ees t at esofmat t er :s ol i d,l i qui d,andgas .Sol i dshav ear i gi ds hape andadefini t ev ol ume.Sol i dshav eadefi ni t ev ol umeandi ndefini t es hape.Gashav ean i ndefini t es hapeandv ol ume.Mat t erhasphy si c alandc hemi c al pr oper t i es .Phy s i cal pr oper t i esi nc l udeodor ,c ol or ,v ol ume,ands t at e.Theyar epr oper t i est hatc anbe obs er v edf r om s eei ng,smel l i ng,ort as t i ng.Chemi c al pr oper t i esar et heabi l i t yt of or m news ubs t anc es .Forex ampl e,bur ni ngwoodc r eat esheatandgas .Mat t erc ango t hr oughps y c hi c alandc hemi c al c hanges .An yc hanget hatocc ur swi t houtal t er i ngt he c hemi c al c ompos i t i onofas ubs t ancei saphy s i c alc hange.Fore x ampl e,c ut t i ngapi ec e ofpaper .Chemi c al changesoc c urwhent hef undament alc omponentorc omponent sof t hes ubst ancec hangesar ec hanged.Thesear ec al l edr eact i ons .Forex ampl e,s i l v er t ar ni s hesbyr eact i ngwi t hai r .Si l v eri sat y peoff undament al s ubs t ancesc al l ed el ement s .El ement scannotbebr ok endowni nt oot hers ubs t ancesandar epur e.When el ement sc ombi neandr eactwi t honeanot hert heyf or mc ompounds .Togof r om mul t i pl eel ement st oac ompound,t heygot hr oughar eac t i on.Thos ear eal l pur e s ubs t anc es .Anot herex ampl eofmat t eri scal l edami x t ur e.Ami xt ur ehasv ar i abl e

4 c ompos i t i ons .Someex ampl esofmi x t ur esar ewi neandwood.Theyc anei t herbe homogenousandhet er ogeneous .Homogenousi swhenas c i ent i stcannots eet he di ffer entc omponent soft hemi x t ur eandc annotdi ffer ent i at et hem f r om oneanot her .I n het er ogeneousmi x t ur es ,as c i ent i s tc ans eet hedi ffer entpar t s .Thesemi xt ur esc anbe s pl i ti nt ot hei rdi ffer entc omponent sbys epar at i on.Theycanbes epar at edbydi st i l l at i on orfi l t r at i on.Di s t i l l at i oni st hes epar at i ngofc omponent si nal i qui dmi xt ur ebyboi l i ngi t andt henc ondens i ngt hev aporandt her es i duet hatr esul t s .Fi l t r at i oni swhenal i qui dor gaspas s est hr oughamedi um t hatc apt ur est hes ol i ds . Chapt er4 Ther ear eabout118k nownel ement sand88oft hes eoc curnat ur al l y .Thenames oft hes eel ement sar eder i v edf r om aGr eek ,Lat i n,orGer manwor dst hatdes cr i besone ormor eoft hei rpr oper t i es .Weus edi ffer ents y mbol st or epr es entt heel ement st omak e i teas i er .Thes es y mbol sc anbeder i v edf r om t heEngl i s hwor dorf r om t heLat i n,Gr eek, orGer manwor d.I nt he18th c ent ur yDal t ons t udi edmat er i al sandt hef ol l owi ngbecame c l eart ohi m mos tnat ur almat er i al sar emi x t ur esofpur es ubst ances,pur es ubs t anc es ar eanel ementorac ombi nat i onofel ement s ,andgi v encompoundsal way scont ai nt he s amemas soft heel ement s .Thet hi r dpar tbec ameknownast hel awofc ons t ant c ompos i t i on.Thenhec r eat edDal t on’ sAt omi cTheor y .I thasfi v epar t sandgoesas f ol l ows:el ement sar emadeupoft i nyat oms,al lat omsi noneel ementar ei dent i c al , at omsf r om di ffer entel ement sar edi ffer ent ,at omsofdi ffer entel ement scombi net of or m c ompounds ,at omsar enotc r eat edordes t r oy eddur i ngr eac t i onsandar ej us ts i mpl y r ear r anged.Compoundsar eex pr ess edwi t hc hemi c al f or mul as .Theat omsar e ex pr ess edbyt hei rel ement ’ ss y mbolandt henumberofat omsi sshownbyt he

5 s ubsc r i pt .At omsar ec ompos edofev ent i ni erpar t i cl esc al l edpr ot ons ,neut r ons,and el ect r ons .As c i ent i stJ . J .Thoms ondi s c ov er edt heel ec t r onswhenhes awt hatel ement s ar er epel l edbyt henegat i v epar tofanel ect r i cfiel d.Si nc et heel ement sdonothav ean ov er al l negat i v ec har ge,heknewt her ewer es omepos i t i v epar t i c l es .Wi l l i am Thomson c ameupwi t ht hePl um Puddi ngt heor yt hatat omshav eapuddi ngofgener al pos i t i v e c har gewi t hnegat i v eel ec t r onsfloat i ngar oundt os t abi l i z ei t .Er nes tRut her f or df ound t hi st obewr ongwi t hhi sex per i ment .Hef oundt henuc l earat om bynot i c i ngt he pos i t i v el yc har gedc ent erofanat om.Thi si swher epr ot onswer ef ound.Then Rut her f or dandJ amesChadwi ckdi s c ov er edneut r ons .Thenumberofpr ot ons , neut r ons ,andel ect r onsi nanat om ar eex t r emel yi mpor t ant .Whent her ear eadi ffer ent numberofneut r onsi nanat om,t heyar ecal l edi sot opes .Whenanat om hasadi ffer ent numberofel ect r ons ,t heyar ecal l edi onsandt heyhav eac har ge.Thenumberof pr ot onsi st heat omi cnumberandt hes um ofpr ot onsandneut r onsi st hemas snumber . Al lt heel ement sar eor gani z edbyi nc r easi ngat omi cnumberi nt heper i odi ct abl e. Chapt er5 Ther ear edi ffer entt y pesofc ompoundsandv ar i ousway st onamet hem.Bi nar y c ompoundsar eei t hermadeupoft wononmet al soranonmet al andamet al .Bi nar y i oni ccompoundsc ont ai npos i t i v eandnegat i v ei onsc al l edcat i onsandani ons .Toname t heseweus et henameofc at i onandbas eoft heani onwi t ht hes uffix“ i de” .Ther ear e t wot y pesofbi nar yi oni ccompounds.T y peIcompound’ smet alc anf or m onl yonec at i on andt y peI I ’ smet al sc anf or mt woormor ec at i ons( cat i onswi t hdi ffer entpos i t i v e c har ges) .Whenwr i t i ngt hef or mul asf ort heseaper s onhast ol ookatt hec har ges ,s o t heyf or m ast abl epar t i c l e.Thes t udent sneedt omemor i z et hec har gesoft het y peI I

6 met al sbutc aneas i l yi dent i f yt hec har gesoft het y peImet al sus i ngt heper i odi ct abl e. Thet y peI Ibi nar ycompoundshav et ol i s tt hec har geoft hemet al af t eri ti nt hef or mul a usi ngr omannumer al s .Bi nar yc ompoundst hatonl yc ont ai nnonmet al sar enamedby usi ngt hef ul l namesofbot hel ement swi t hdi ffer entpr efi x es .Thepr efi x esr epr es entt he numberofat omsi nt hec ompound.Anot hert ypeofi onsi sc al l edpol y at omi ci ons .They ar ec har gedent i t i escomposedofs ev er alat omsboundt oget her .Thesear eass i gned s pec i alnamest hats t udent smus tmemor i z e.Forex ampl e,NH4+i sc al l edammoni um. I oni ccompoundsal s omaycont ai npol y at omi ci ons .Thenami ngofpol y at omi ci ons f oundi ni c oni cc ompoundsi ss i mi l art obi nar yc ompounds .Nami ngi oni ccompounds c ont ai npol y at omi ci onsi ss i mi l art onami ngbi nar yc ompounds .Ac i dsar esubst ances di s s ol v edi nwat erwher ec er t ai nmol ec ul espr oduc eH+i ons .Tonameac i dswhent hey donotcont ai nox y geni nt hei rani ons ,aper s onwi l laddt he“ hy dr o”pr efi xandt he“ i c ” s uffix .Forex ampl e,whenHCl i sdi s s ol v edi nwat er ,hydr oc hl or i cac i di sf or med.When t heani ondoescont ai noxy gen,t he“ at e”or“ i t e”i sr epl ac edwi t h“ i c”or“ ous ” .The s t udent ss houl dal s obepr epar edt owr i t et hef or mul af r om t henamegi v en. Chapt er6 Tok nowwhenac hemi c al c hangehast ak enpl ac eas t udentneedst ol ookf or v i s ualc l ues.Theyi nc l udec ol orc hange,s ol i df or mat i on,gas eousbubbl espr oduc ed,a fl ameocc ur s ,heatpr oduced,orodori ssens ed.Chemi c al c hangesal way shav et odo wi t ht her ear r angementofhowt heat omsar egr ouped.Forex ampl e,whenmet haneand ox y genc ombi ne,c ar bondi ox i deandwat erar epr oduced.Thes er eac t i onsc anbe r epr es ent edwi t hac hemi c al equat i on.Ac hemi calequat i ons howst henumer i c al r el at i ons hi pbet weent hepr oduc t sandr eac t ant sofachemi c alc hangewi t hpr oduct son

7 t her i ghts i deofanar r owandr eac t sandt hel ef tsi de.Thear r owi sas i mpl ef orwhati s pr oducedandi sr eadas“ yi el ds ” .Thi si swheni ti si mpor t antt or emembert hati na c hemi c al r eact i on,at omsar enei t herc r eat edordest r oy ed.Ther ef or e,al lt heat omsofa c er t ai nel ementonones i de,mus tbepr esentont heot hers i de.Thi smeanst he equat i onneedst obebal anced.Webal anc edequat i onsbyaddi ngc oeffici ent si nf r ontof t hecompoundsorel ement st hatar es t andi ngal one.I tmus tber emember edt hat c ompoundswi l l nev erbec hangedi nbal anc i ngr eac t i onsands ubsc r i pt swi l l r emai nt he s ame.Forex ampl e,t hec hemi c alequat i onN2+H2 NH3i sunbal anc ed.Byk eep t r ac k i ngoft henumberofat omsi neac hel ementandcompoundwec anbal anc ei tt o bec omeN2+3H2 2NH3.Thepr oces si nc l udest r i alander r orwhi c hc anbe f r us t r at i ngbutwi t hpr act i c ei twi l l bec omeeasi er .I naddi t i ont obal anc i ngequat i ons , s c i ent i s t sal s ok eept r ackoft hei rphy s i c als t at es.Thephy s i cal s t at esofr eact or sand pr oduc t sar et hef ol l owi ng:s ol i d( s ) ,l i qui d( l ) ,gas( g) ,di s sol v edi nwat er( aq) .Thes ear e wr i t t eni nt hes ubs c r i ptposi t i onaf t ert henumberofat oms .Tol ear nt hes e,y oumus t memor i z eel ement sandcompoundsnat ur al s t at esandwhatt heycombi net of or m.For ex ampl e,s ol i dc ar bonr eact swi t hox y gengast of or mc ar bondi ox i degas .

Chapt er7 Ther ear ec er t ai nt endenc i esi nr eac t ant st hatmak et hem wantt of or m pr oduc t s . Themos tc ommont endenc i esar et hef ol l owi ng:f or mat i onofas ol i d,f or mat i onofwat er , t r ans f erofel ec t r ons ,andf or mat i onofagas .Tot el lwhet herachemi c al c hangei sgoi ng t ooc c urbet weenchemi c al swemus tr emembert heset endenci es .Thes ol i dt hatf or ms i nc hemi c al r eac t i onsi scal l edapr ec i pi t at e,whent hi shappensi ti scal l edapr ec i pi t at i on

8 r eac t i on.Anex ampl eoft hi shappeni ngi swhenwat erc ont ai ni ngbar i um ni t r at er eac t s wi t hpot ass i um c hr omat eandf or msy el l ows ol i df or ms .They el l ows ol i df or mat i oni s pr oofofac hemi cal c hange.Wheni oni cc ompounddi ssol v esi nwat ert hei onsar e s epar at ed,andas ubs t ancecal l edas t r ongel ec t r ol y t ei sf or med.Forex ampl e,when Ba( NO3) 2i sdi s s ol v edi nwat er ,i tpr oducesBa2+,NO3,NO3–whi c har es epar at edi n t hewat er .T odec i dewhatpr oduc t swi l lbef or medi nac hemi c al r eact i onbef or e pr ef or mi ngt heex per i menti sex t r emel yhar d( ev enf orac hemi s t ) .Ac hemi stc ant r yt o i dent i f yt hel i k el i hoodofeac hpos s i bi l i t yandt henmak eaneducat edguess .I tc anonl y bet r ul ydet er mi nedaf t erpr ef or mi ngt heex per i mentandex ami ni ngt her esul t s .Oneof t heway st obec omebet t eratmak i nganeduc at edgues si sk nowi ngt hegener alr ul es f ors ol ubi l i t yofi oni cc ompoundsi nwat er .Theyr eadast hef ol l owi ng:mos tni t r at e ( NO3)s al t sar es ol ubl e,mosts al t sofNa+,K+,andNH4+ar es ol ubl e,mostchl or i de s al t sar es ol ubl e,mos ts ul f at esal t sar esol ubl e,mosthy dr oxi dec ompoundsar es l i ght l y s ol ubl e,andmostsul fi de,c ar bonat e,andphosphat es al t sar es l i ght l ys ol ubl e.Topr edi ct pr ec i pi t at esol i dswhent woi oni cc ompoundsar emi x eds t udent smus twr i t et he r eact ant sast heyex i s tbef or et her eac t i on( r ememberwhensal t sdi s s ol v est hei ri ons s epar at e) ,c ons i dert hev ar i ouss ol i dst hatc oul df or m( ex c hanget heani onsoft he addeds al t s )andt henus et hes ol ubi l i t yr ul est opr edi ctt hei dent i t yoft hes ol i d. Memor i z i ngot herf act swi l l al s obehel pf ulwhenpr edi c t i ngpr oduct s .Li k ewhenas t r ong aci dandbas er eac tt heywi l lf or m wat erands al t .Whenr eact i onsbet weenmet al and nonmet alhappenandt her ear eat r ans f erofel ec t r ons ,i ti sc al l edox i dat i onr educ t i on r eac t i on.Ther ear eal s odi ffer entt y pesofr eact i ons .Thet y pesar es y nt hesi sr eac t i on, dec ompos i t i on,andcombus t i on.

9 Chapt er8 Count i ngbywei ghi ngi swhenaper s onwei ghss omet hi ngsonas c al eandt hen di v i desbyhowmuc heac hi ndi v i dualt hi ngwei ghed.Li k ei nac andys t or ei ns t eadof c ount i ng100j el l ybeansi ndi v i dual l ywecanas s umet heyal l wei gh5gr amsandwei gh out500gr amswor t h.Wec andot hi sbec aus ewek nowt heav er agemassoft hebeans . Wecandot hi swi t hel ement s .Si nceat omsar et oosmal lt os ee,wemus twei ghl ar ge s ampl est ofi gur eouthowmanyat omsar epr es ent .Theuni tt hatgoesal ongwi t hat oms i samu.Amus t andsf orat omi cmassuni tandi sus eds i nc eat omsar es omuc hs mal l er t hant heus ual obj ec t swewei gh.1amui sequal t o1. 66x 10^ 24g.Tobeabl et oc ount t heseat omsweus et heav er ageat omi cmas sf ort heel ement .Wewei ghl ar gesampl es oft heel ementandt hendi v i debyt heel ement ’ saver ageat omi cmas st ofi ndouthow manyat omsoft hatel ementar epr esent .Anot hernumbert hatwemus tmemor i z ei st he mol e.Themol ei sanumberequal t ot henumberofcar bonat omsi n12. 01gr amsof c ar bonandc anbeus edt odes c r i bev er yl ar genumber s .Thi snumberi sc al l ed Av ogr adr o’ snumberandi sequal t o6. 022x 10^ 23uni t sofas ubs t anc e.Conv er t i ng bet weent hedi ffer entuni t sgi v eni sc r uc i al .Togetf r om gr amsofas ubs t ancet omol es ofas ubs t anc eaper s onhast odi v i debyt hemol armas soft hes ubs t ance.Tofi ndt he mol armassaper s onmus taddal lt hemas snumber sf oundont heper i odi ct abl e t oget her .Themassnumberi st henumberundert heel ements y mbol ont heper i odi c t abl e.Whent heel ements y mbol i swr i t t ennotont heper i odi ct abl e,i ti sf oundont het op l ef t .T ogof r om mol est ogr ams ,aper s onneedst omul t i pl ybyt hemol armas s.Togo f r om mol est oat omsofas ubs t anc e,t heper s onneedst omul t i pl ebyAv ogadr o’ s number .Tofi ndt hemol esofas ubs t anc ef r om t henumberofat oms ,t heper s onneeds

10 t odi vi debyAv ogadr o’ snumber .Conc ept ual pr obl em s ol vi ngi sk eyt obes uc c es s f ul i n c hemi s t r y .St udent smus tbeabl et osol v enewpr obl emsont hei rownbyus i ngc oncept s andf or mul ast hathav ememor i z ed.Tost ar tawor dpr obl em as t udentmus ti dent i f ywhat i st r y i ngt obef ound.Thent heymus tdec i deonhowt ogett her e.Oncet heans werhas beenf oundt hes t udentmustr ec hec kt hepr obl em andmak esur et hei rans wermak es s ense.Anot heri mpor t ants k i l lt ohav ei sbei ngabl et ofindt heper c entc ompos i t i onof c ompounds .Tofindt heper c entc ompos i t i onaper s onwi l l findt hemas soft heel ement pr es enti nonemol e( mol armas s ) ,di v i debyt hemassof1mol eoft hec ompound( t he el ement s ’ mol armas ss um) ,andmul t i pl eby100%.T ofindt hef or mul aoft hecompound wemus tus et heempi r i c alf or mul aandmol ec ul arf or mul a.Theempi r i c alf or mul ai st he r at i ooft heel ement soft hes ubs t anc ei ns i mpl es tf or m.Themol ec ul arf or mul ai st he act ual r at i oofel ement soft hes ubst anc e.T ofi ndt heempi r i c alf or mul af r om per c ent sof t hei ndi v i dualel ement swemus tc onv er tt heper cent st ogr ams .Thenwemus tconv er t t hegr amst omol esus i ngt hemol armas s es .Thenwemus tdet er mi newhi c hi st he s mal l es tandt hendi vi deal lt hev al uesbyt hi snumber .Wewr i t et heempi r i c al f or mul aby at t ac hi ngt hes ewhol enumberr at i ost ot hes ubs c r i pt soft hec hemi cal s y mbol sofeac h el ement .Tofindt hemol ec ul arf or mul awemus tdi v i det hemol ec ul armas sbyt he empi r i c al f or mul amas s .Thenwemus tmul t i pl eeac hs ubs c r i ptoft heempi r i c al f or mul a byt hi snumber . Chapt er9 Chemi c al equat i onss howust hepr oduct sandr eac t ant sofc hemi calr eact i ons . Theygi v eust her el at i v enumber sofmol ec ul espr esenti nt her eac t i ons .I ti si mpor t ant t ok nowhowt obal anc eequat i onss ot hatwec ank nowt hecor r ec tr el at i v er at i oof

11 el ement s .Forex ampl e,t heunbal ancedCO +H2 CH3OHs howst hei nc or r ect r el at i v er at i o.Tobal ancet hes eequat i ons ,wemus tus et r i al ander r orunt i l wecomet o t hecor r ec tbal anc edequat i on.Thebal ancedequat i onf ort hi sonei sCO +2H2 CH3OH.No wwecanus et heequat i ont opr edi c tt hemol esoft hepr oduc t st hatagi v en numberofmol esofr eact an...