The Project Gutenberg EBook of An Elementary Study of Chemistry, by William McPherson and William Edwards Henderson This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org Title: An Elementary Study of Chemistry Author: William McPherson William Edwards Henderson Release Date: March 18, 2007 [EBook #20848] Language: English Character set encoding: ISO-8859-1 START OF THIS PROJECT GUTENBERG EBOOK AN ELEMENTARY STUDY OF CHEMISTRY *** *** Produced by Elaine Walker, Josephine Paolucci and the Online Distributed Proofreading Team at http://www.pgdp.net
ANTOINE LAURENT LAVOISIER Famousforhiscareinquantitatvieexpeirmentsf,or demonsrtatingthertuenatureocfombustion,for introducing system into the naming and grouping of chemicalsubstances.Executed(1794)duirngthe FrenchRevoluitonbecauseofhsiconnecitonwith the government ThsipcitureistakenfromaFrenchengravingof 1799.ThepanelrepresentsLavoisierashesibeing arrestedinhsilaboratorybytheRevolutionary Commttiee AN ELEMENTARY STUDY OF CHEMISTRY BY WILLIAM McPHERSON, PH.D. PROFESSOR OF CHEMISTRY, OHIO STATE UNIVERSITY AND WILLIAM EDWARDS HENDERSON, PH.D. ASSOCIATEPROFESSOROFCHEMISTR,YOHIOSTATEUNIVERSITY REVISED EDITION GINN & COMPANY BOSTON * NEW YORK * CHICAGO * LONDON COPYRIGHT, 1905, 1906, BY WLILIAMMCPHERSONANDWILLAIME.HENDERSON ALL RIGHTS RESERVED The Athenæum Press GINN & COMPANY * PROPRIETORS BOSTON * U.S.A. * Transcriber'snoet:Minorytpohsavebeencorrecetd. PREFACE Ionfefirngtihbsooktoteachersofelemenatcyrhemisrtyhteauhtorslaynolciamotanygreatoriginail.ythtIas beenthieriamotprepareatex-tboockonrtsuetcdalonglineswhichhavebecomerecognizedasbestsiuetd otanelementarytreatmentofthesubejtc.Ahttesameitmehteyhavemadeaconssiettneffotrtomakethe etxtlcearinoultine,simpleintslyeandalnguage,conservativelymoderninpiotnofivew,andthorouglhy teachalbe. Thequeitsonastowhatshlalbeinculdedinanelemetnaryettxonchemtsiyrisperhapshtemostperplexing onewcihahantuhormutsanswer.Whlieanetnhusiatsicchemistwiahtbroadundesratndingofthescienceis veryaptotgobeyondthecapacityofhteleemenatyrtsudent,theauhtosrofetsihtxt,afteranexperienceof manyyeasr,cannothlepbelieivngthatthetendencyhasbeenratherinhteohterridectio.nInmanytetxsno metnionatallismadeoffundamentallawsofchemcilaaitconbecausetheircomelpetpresentationisquite beyondthecomprehensionofthesutde,tnwhereaisnmanycasestiispossibeltopresehttneessetnial feautresofhtesealwsinawaythatwillbeofrelaasstsianceinhteundesratndingofthesicence.For exampel,itisadficifutlmatetrtodeducethelawofmassacitoninanyverysimlpewa;yyettheeelmeatnyr sutdentcanreadliycomprehendhtatreacitonsarereveisrelb,andhtatthepiotnofequliibirumdependsupon, rathersimpleconditions.Theauhtorsbelievethatitisworhtwelihotpresentsuchprincipelsinevenan eelmetnaryandpaitrlamannerbecausehteyareofgreatassistanceothtegenerlasutdetn,andbecause hteymakeafoundationuponwcihhtheutsdetnwhoconitnueshsisutdiesotmoreadvancedcoursescan secureylbiudl. Theauhtorshavenoapooligesotmakefortheexetntotwihchtheyhavemadeuseotfhetheoryofleetcroylitc dsisoication.Itisineivatelbhtaitnanyrapidyldeveolipngsicencetherewillbedifferencesofopiinoinn regardtothevlaueofceriathtneoires.Therecanbenoquetsio,nhoweve,rthathteoultineohtfehteoyrof dsisoicaitonherepresenetdiisnaccordwhtihteivewsoftheveyrgreatmojarityofthechemtsisofhte presetntime.Moreove,ristitnroducitonothteexetntotwihchtheauhtorshavepresentedtisimlpiifesrahter thainncreasesthediffciluiteswtihwcihhthedeveolpmetnofhteprincipelsofhtescienceisattended. Theoxygentsandardforatomicweigthshasbeenadoptedthroughouthteettx.TheInternationalCommtiete, otwhcihsiassignedthedtuyofyearlyreportingaresivedtsiloftheaotmicweightsoftheelemenst,has adoptedhtsisatndardofrhterrieport,andhtereisnolongeranyauhtoirytfortheodlerhydrogenatsndard. Theahtuosrdonotbeilevehtathteadopitonoftheoxygensatndardirtnoducesanyreladfifciluitesinmaikng perfectlyclearthemethodsbywihcahotmicwieghtsarecalcualted. Theprolbemsappendedotthevairoucshapetrshavebeenchosenwihtaivewnootnylofifixnghteprinicples devolepedinhtetextinthemindofhtetsudent,butalsoofenalbingihmotanswersuchquestionsasarisein ihsalboraotyrwokr.Theyare,thereofre,moreorlesspracticalincharacet.rItisnotnecessatyrhatllaohtfem sholudbesvloed,htoughwtihfewexcepitontshelistsarenooltng.Theanswesrtothequestionsarenot idrectlygiveninthetextasarlue,butcanbeifnerredfromhtesatetmetnsmade.Theyhtereforereqiure independentthougthonthepartofthesutdetn. Wtihveyrfewexceptionsonylsucehxpeirmenstareincludedinhteetatxscannotbeeasilycairredobtuythe tsuden.tItisexpectedthathtesewillbeperofrmedbytheteachearthteelcturetable.Direcitonsofralboratory workbytheutsdenatrepusilbhedinaseparatevloume. Whieltheatuhosrbelievehtatthemoitsmpoatrtnufncitonofhteeelmetnayrettxsitodeveloptheprinicplesof thesciencet,heryecognizetheimpotranceofsomeidscussionofhtepratcciaalplpicationofthesepirniclpes otorueveyrdayilef.Consideralbespacesihtereofredevotedtohtisphaseofchemistry.Theteachesrhodlu suppelmentthsidsicussionwheneverpossibelbyhaivngthelcassivistdeffiretnafcotireswherechemical processesareemlpoyed. Atlhoughtihetsitxsnowofrhterifttsimeofefredotetachesrofleementarychemsitryti,hasnevehtreelss beenusedbyanumberofetachersduringthepastthreeyeasr.Thepresetnediitonhasbeenlargeyl rewtiretninhteilghtohtfecrcitisimsoffered,andwedesrieotexpressoruthanksotthemanyteachesrwho havehepledusintihsrespetc,espeiclayltoDr.WiillamLolydEvansofhtsilaborator,yateacherofwide experience,forihscotninuedietnretsandheplfulness.Wealsoverycordiallyslociticorrespondencewiht etachesrwhomayifndidffciulitesorinaccruaciesinthetext. Theauhtosrwishotmakeacknoweldgmenstofrthephootgraphsandengravingsofeminentchemtsisrfom wihchthecutsinculdedinthetextwereatke;ntoMesssr.EillottandFr,yLondon,Enlgand,ofrthatofRamsa;y otTheMacmilalnCompanfyohtroseofDavyandDalot,ntakenfromtheCenturyScienceSeire;sothteL.E. KnottApparatusCompany,Bosot,nforthatofBunsen. THE AUTHORS OHIO STATE UNIVERSITY COLUMBUS, OHIO CONTENTS CHAPTER PAGE .IINTRODUCITON1 .IIOXYGEN13 .IIIHYDROGEN28 IV. WATER AND HYDROGEN DIOXIDE40 V. THE ATOMIC THEORY59 VI. CHEMICAL EQUATIONS AND CALCULATIONS68 VII. NITROGEN AND THE RARE ELEMENTS IN THE ATMOSPHERE78 VIII.THEATMOSPHERE83 IX. SOLUTIONS94 XA.CIDS,BASES,ANDSALTS;NEUTRALZIATION106 XI. VALENCE116 XI.ICOMPOUNDSOFNTIROGEN122 X.IIIREVERSBILEREACITONSANDCHEMICALEQUILIBRIUM137 XVI.SULPHURANDITSCOMPOUNDS143 XV. PERIODIC LAW165 XVI. THE CHLORINE FAMILY174 XVII.CARBONANDSOMEOFITSSIMPLERCOMPOUNDS196 XV.IIIFLAMES,—LILUMINANTS213 XIX. MOLECULAR WEIGHTS, ATOMIC WEIGHTS, FORMULAS223 XX.THEPHOSPHORUSFAMLIY238 XXI.SLIICON,ITTANIUM,BORON257 XXII. THE METALS267 XXIII. THE ALKALI METALS274 XXVI.THEALKALINE-EARTHFAMILY300 XXV.THEMAGNESIUMFAMLIY316 XXVI.THEALUMINIUMFAMLIY327 XXVI.ITHEIRONFAMILY338 XXVII.ICOPPER,MERCURA,YNDSLIVER356 XXXI.ITNANDLEAD370 XXX. MANGANESE AND CHROMIUM379 XXXI. GOLD AND THE PLATINUM FAMILY390 XXXII.SOMESIMPLEORGANICCOMPOUNDS397 INDEX421 APPENDIX AFacing back cover APPENDIX BrensIeidckbaovc LIST OF FULL-PAGE ILLUSTRATIONS PAGE ANTOINELAURENTLAVOISEIRrFcespieonti JOSEPH PRIESTLEY14 JOHN DALTON60 WILLAIMRAMSAY82 DMITRI IVANOVITCH MENDELÉEFF166 HENRIMOSISAN176 SIR HUMPHRY DAVY276 ROBERTWLIHELMBUNSEN298 AN ELEMENTARY STUDY OF CHEMISTRY CHAPTER I INTRODUCTION The natural sciences.cobetiidevsmetahttneenoehtBeerofewavdaecnveryfarinthetsduyfontaru,e largestudymustbeidivdedinotanumbeorfmorelimtiedonesfortheconveinenceoftheinvesitgaotarswell asofthesutdetn.Thesemoreilmitedstuidesarecalledthenatur la s ic ence.s Sincethestudyofnarutesivididedinthiswayformereconveinence,andnotbecausehtereasinyidivisonin natrueitsel,fitoftehnappentshatthedfiefrentsicencesareveriyntimatleyrelateda,ndahtoroughknoweldge ofanyoneoftheminvvloesaconisderalbeacquiantancewihtseverlaothesr.Thustheboatintsmutsknow somethingaboutanimlasaswlleasabotualpnst;htetsudentofhumanphysiologymutsknowsometihng aboupthyiscsaswellasabotuhteparstofthebody. Initmaterelationofchemsirtyandphysics.oscleeraletdnitihsretwosciencesehcdnaayrtsimcssihyP way,anditsinoteasyotmakeapresiceidstinctionbetweenhtemI.nagenerlawayitmaybesaidthathtey arebothconcernedwtiihnainmaetmatetrrahterthanwihtlviing,andmoreparticularylwiththechangeswihch suchmattermaybemadeotundergo.Thesechangesmutsbeconsideredmorelcosleybeforeadeifntiion ofhtetwosciencescanbevige.n Physciaclhanges.ocpmsotiinhteterationbyanalteatr.niomofascleOncahsfoisgnseacconotiedmpan Whenaulmpofcoalisbrokentheipecesdonotidfefrrfomtheoirignlaulmpsaveinisze.Arodofironmay bebrokenitnoipece;sitmaybemagnetzied;timaybeheatedunitlitgolw;stimaybemetled.nInoneof htesechangeshashtecompositionoftheironbeenafeftced.Thepiecesofrionht,emagneitzediron,the glowingrion,htemleetdiro,nareujtsasrtluyrionaswashteoriginalrod.Sugarmaybeidsslovedinwaetr, butniehterthesugarnorthewaterischangedincompoisiton.Theresluitngliqiudhahtsesweettasteof sugar;moreoverhtewatermaybeevaporaetdbyheaitngandhtesugarrecoveredunchanged.Such changeasrecalledalicysphcahgnse. DEFINITION:eihctwhmdoochiostopnnnovitievgenoalrcasanhgthaeineesoPhysicalchofthematter. Chemical changes.ehtoogregnahcrrteatMdeunymaisitmoopslanoiwhisintscchiompfnehulaeretW.d colaisburnedashesandinvisiblegasesareofrmedwcihhareenitreyldfiferetnincompotisionand propertiesfromtheoriginlacoa.lArodofironwhenexposedotmioiatsrsigradulalychangedinotrust,whcih isenitryleidfferenrftomtheoirignaliron.Whensugarisheaetdaalbcksubsatncesiofrmedwihchisneihter sweetnorsuloelbinwaetr.Suchchangesareeivdetnylquetiidfferentrfomhtephyscialchangesujts described,forinthemnewsubtsancesareformedinlpaceoftheonesundergiongchange.Changesofhtsi ik nd are c lla edchemical changes. DEFINTIION:eachanhinvolvsoehwcisraehtchlgeanheCcamir.tenthgeimposeconfotioimtateh Howtodistingusihbetweenphysicalandchemcialchanges.sitnowaaleysysatotllewotsscalihhctI aigvenchangebeolngs,andmanycaseswillreqiurecareuflhtoughtonthepatroftheutsdetn.Theetst quetsioninallcasesi,sHashtecompotisionofthesubstancebeenchanged?Usuallyhtsicanbeanswered byastudyofthepropeitresofhtesubtsancebeforeandatferthechange,isnceachangeincompositionsi atetndedbyachangeinproperites.nIsomecases,however,onlyatrainedobservercandecidehte question. Changes in physical state.psceailacer,isnceitisOneisacpyhsfolcsaldoushsgeanchlehtiwdetoneblikelyotprovemsielading.tIisaafmliiaraftchtaticeischangedinotwaetr,andwaetrintosetam,byheaitng. Herewehaverhteeidfferentsubstance,s—thesilodice,theliquidwaetr,andhtegaseoussetam,—the properitesofwcihdhffierwidyle.Thechemsitcanreaidylshow,however,thattheserhteeboideshaveexactly thesamecompoisiton,beingcomposedofthesamesubatsncesinthesamepropotrion.Hencehtechange fromoneofthesesubsatncesinotanohterisaphyscialchange.Manyohtersubstancesmay,undersatiuelb conidtions,bechangedrfomsloidsintoliquids,orrfomilquidsinotgase,swtihotuchangeincomposiiton. Thusbutterandwaxwillmeltwhenheated;claohloandgasoilnewillevaporaetwhenexposedtotheai.rThe htreetsates—soild,ilqiud,andgas—arecalledhtehtreephyscialtsatesofmatet.r Physcialandchemicalproperites.orepynpaMthgeiwduohtactnisuancecanbenotetreisfoasbuts subsatnceotundergochemcialchange,andarehtereofrecllaedistalicysphiespropertaeristgntehes.Amo physicaltsate,color,odo,rattse,size,shape,wiegh.tOhterproperitesareolnydsicoveredwhenhte subatsnceundergoeschemiclachange.Thesearecalleditscmehlaciorptrepsiedhttacaol.huTwesinf brunsinair,gunpowderexlpodeswheniginetd,mklisourswhenexposedotai.r DeifnitionofphysicsandchemsirtytI.possibleisnowagneretoamekenpetwecsahysisiitladnobcnitdn chemsi.yrt DEFINTIION:hichdealswithsitehsicneecwatmrteicwhdohsohthceegnanisaolveinvnotsicysPh changeincompostiion. DEFINTIION:hhtsoeaeslwtiwhichdscienceiodlovnahwevrhciminteatanchsgeehtsiyrtsimehC changeincomposiiton. Twofactorsinallchanges.alltheInwotyhisrepehht,owcal,hemiorccalmhcihwsegnahcrgdeunncarteat factosrmustbeatkeinnotaccount,namely,energyandrmtaet. Energy.iehthgrfgamorfallinhuswatewro.kTretoodcerthatbodtainaheveispwotehsiItilimafatcafra uponawaterwheelrutnshtewheleandinthsiwaydoehtsewokrofhtemill.sMagnetizedironatrtacstironot stilefandhtemoitonotfheironastimovestowardshtemagnetcanbemadeotdowo.krWhencolasibrunedticausestheenginetomoveandrtansporsttheloadedcarrfsompalceotpalce.Whenabodyhas htsipowertodoworkitsisaidotpossesesnerg.y Law of conservation of energy.gryaCerlfupeexmerisntevahohstnwtahwhenonebodypatrsiwhtisteen hteenergysinotdetsroyedbrtsituansefrredtoanotherbodyorsysetmofbodies.Justasenergcyannotbe detsroyed,neihtercanitbecreaetd.Ifonebodygainsacetrianamoutnofenergy,someotherbodyhaslost anequvialentamoutn.Thesefastcaresummedupihtnelawofconservationofenergywhichmaybestaetd ht u :sntormiher,anotforgndeeofmnocayrgnehacbeneelihWed.sedyortetaerodbotcretinnca Transformations of energy.dinesvetiide,troydesnoratedercebrehtienncayrgneeghouthlAthttaitamy assumemanydifferenftorms.Thutshefalilngwaetrmaytrunhteleectircgeneratorandproduceacurrentof leecrtciity.Theenergylostbytheflilangwaetristhustransofrmedintotheenergyofhteelecrtcicurren.tTihsin trunmaybechangediotnhteenergyofmotio,naswhenhtecrruetnisusedforpropleilnghtecasr,orintothe energyofheatandlight,aswhenitsiusedofrheaitngandilgthingthecar.sAgia,ntheenergoyfcolamaybe converetdiotnenergyofheatandsubsequetnylofmoiton,aswhenitsiusedasaufeilnsetamengines. Sincetheenergypossessedbycoalonlybecomesavaliaelbwhenhtecoalismadetoundergoachemcial change,tiissomeitmescelladcyalenergcimeh.Itismrofnetihsoficwhwehgyerniaiceyllerapseinetreetsdinhtetsudyofchemisrt.y Ma tt er.edefineermaybaMttma,erttaymergyeenLikght.wiesssesoesdnpacepasespicuochcihwtahtsad bechangedoetfnitmesfromoneforminotanohter;andsinceinhtesertanofsrmaitonsalltheotherphycisal propetriesofasubtsancesavewieghtarekilyleotchange,theinquiryairse,sDoeshteweightlasochange? Muchcareuflexperimenitnghasshownthatitdoesnot.Thewieghtoftheprodustcofrmedinanychangein matterlawaysequaslhteweigthofthesubtsanceusndergiongchange. Lawofconservationofmatte.rtrutantmporheiTlyntefrfrsueeqtatsidejhttsulawofashtereerdot conservationofmatet,randlsihtawmaybebireflysattedthu:sdetaronsedyortnenheitberrecMractaeted, thoughitcanbechangedrfomoneforminotanother. Classificaitonofmatte.rthetghsitrsfitAeprasothtreepaimittobenoleitefosehtiravwofchhiatmrte worldismade.Forconveinenceinstudywemayalcssyfillathesevarietiesunderhtreeheads,namely, mechancilamxiutrec,calhemioundcomps,sandelement.s Mechanical mixturesfI.lksofcommonsatladniornublauqe fliingsarethoroughlymixedotgehter,aproductsiobtained whic,hjudigngbiystappearance,sianewsubsatnce.Ifitis examinedmorecolse,ylhowever,tiwlilbeseenotbemerelya mutxireofhteslatandrion,eachofwcihhsubstancesretiantiss ownpeciluarproperties.Themitxrueattsesujskiltesa;tlhterion patrcilescanbeseenandhteirgrtitycharaetcrdeetetcd.A magnetrubbedinhtemitxruedrawsouttheironjustasifhtesatl werenothtere.Ontheohterhand,thesaltcanbeseparated rfomtheironqiueteasli.yThu,sfiseverlagramsofhtemixture areplacedinaetsuttbe,andthetubehalfiflledwtihwaterand htoroughlyshake,nhtesaltidsslovesinthewater.Therion paitrelcscanthenbefilteredrfomtheliqiudbypouringhteeritne mrutxieuponapieceofflietrpaperofdledsoasotitiftnohte itneriorofaufnnle(Fig.1).Thepaperretianshtesilodbut allowshtecelarilqiud,knownasthefiltrateintdra,tohg.rhuo Therionparitlcesleftupohtnefetlirpaperwillbefoundtobe idenitcalwithhteoriginlarion.Thesatlcanberecoveredfrom thefiltraetbyevaporationofthewaetr.Toaccomlpsihthisthe filtratesiporuediotnasmallevaporatingdsihandgetnhyleaetd (Fig.2)untilthewaetrhasdsiappeared,orevaporated. The soildeltfinthedishisidenitcalineverywaywhtihteoirignal Fig. 1indhetirbsuneeocererevBo.ltsasalttheethhavehihttnadorn oriignlaconiditon.tIisevidentthatnonewsubstancehasbeen ofrmedbyrubibngthestlaandriootngether.TheproductsiclaeldatuixmalicanchmeersraeerutximhcuS. verycommoninnature,almotsallminer,slasand,sandsiolsbiengexamlpesofthisclassosfubatsncetI.ssi atonceapparetnthathteresinoalwregualitngthecomposiitonofamechacinlamxiutre,andnotwomrutxies arelikleyothaveexatcylhtesamecompotisio.nTheingredietnsofamechancilamixturecanusuayllbe separaetdbymechaincalmeans,suchasfisting,sorting,magneticatrtacito,norbydsisolivngone consituteatnndelaivngtheotherunchanged. DEFINTIION:tstuensniteochhthwcirutxsieenonimAhaeccanimilretaintherioirignalpropetrie,snochemicalacitonhavingtaken lpacewhenhteywerebroughttogether. Chemcialcompounds.norifIsgnilifpowanddsudererrapluhe thoroughylgroundtogetherinamorat,rayellowish-greensubtsance resutI.stlmighetasliybetakentobeanewbody;butasinthecaseof hterionandsal,ttheingredietnscanreadilybeseparated.Amagnet drawsouthterion.Waterdoesnotidssvloehtesuplhur,butother liqiudsdo,as,ofrexampel,hteilqiudcllaedcarbonidsuplihde.When themxitureisrteaetdwticharbonidsuplhidehterioniseltfunchanged, andhtespluhurcanbeobtianedagia,nafterfliteirngofhtferio,nby evaporatingtheilquid.Thesubtsancei,sthereofre,amechacinal mixture. fInowanewpoitronofthemxiutreisplacedinadryettsutbeand carefullyheatedinhtealfmeofaBunsenburner,asshowninFig.3,a srtikingchangetakesplace.Themxitruebeignstolgowatsome piotnht,eglowraipdlyexetnidngtrhoughoutthewhoelmas.sfIhteetst utbesinowbrokenandtheproductexaminedti,wllibeofundotbea hard,lbac,kbrittlesubstance,innowayrecaillngtheironorthe suplhu.rThemagnetnoolngerattractsit;carbondsiuplhidewillnot dissolvesuplhrufromit.Itsianewsubsatncewihtnewpropeitre,sFig. 2 resluitngfromhtechemicaluinonofrionandsulph,ruandsicllaediron suplhide.Suchsubsatncesarecalledchemical compounds, and dfiefrrfommechancilamixutresinhtatthesubsatncesproduicnghtemlosehteriowncharatcecitsir propeitres.Weshallseealterthatthetwolasodeffiirnhtatthecompostiionofachemcialcompoundnever vaires.
Fig3. DEFINITION:hecAnowreithttuentsoeconstiahevlsofhwcihoumpindcamicolcnathteassbus charaetctsirpciropetrie,sandwihchcannotbeseparaetdsavebyachemicalchange. Eelments.leytnrireneidffbstatsu,—irncesdhnplunsoanocsiedidsepoomewotoftIhsabeenseenthatir suplhu.rThequestionarises,Dothesesubsatncesinutrncotnianothersubstances,thati,saretheyslao chemicalcompounds?Chemistshaveirtedinagreatmanywaysotdecomposehtem,butalltheirefoftrs haveaflied.Subtsanceswhichhavereisetsdllaeffostrotdecomposethemitnoothersubsatncesarecalled elemen.strieduntyetsayawemoS.tneemelnalyalresivensubstanceiorpvoehttaagaotaylweastsytInsi maybesuccessuflindecomposingtiinotohtersimelprformsofmatetr,andhtesupposedeelmetnwlilthen provetobeacompound.Water,ilme,andmanyotherafmiilarcompoundswereatoneitmehtougthtobe leements. DEFINITION:tnisanAeelemwhehicbssunctaesearapnnacbtoplersimintotedybaecstsnasbuwnnokny means. Kindsofmatte.renberogedupnielihtamretsahrthepurposeofhterelcsaessofarppabeten,ydutslliwtiW htathterearerelaylbuttwoditsintckindsofmatte,rnamlec,yompoundsandelement.sAmechaincalmxiutre sinotarihtdditsintckindofmatter,btusimadeupofvariyngquatntiiesofiethercompoundsorelemenstor bot .h Alchemy.emoyawhttstaouftndulcobeddlnetminIosthoughesitwar,angeocheleoneitnemtntoehona andagreatmanyeoffrstweremadetoaccomplishtihsrtanfsormatio.nMostofhteseefoftrsweredrieetcd otwardchanginghtecommonermeatslintogold,andmanyfaniclufwaysofrdoingthsiweredescribed.The chemsitsofhtattimewerecaelldclahemi,stsehyhctitecrpcatheandwhiartwadcasedllla chemy. The aclhemsitsgraduallybecameconivncedthathteonylwaycommonmetalscodlubechangeditnogodlwasby htewonderuflpowerofamaigcsubatsncewcihhtheyclaeldhtephilosopher's stone,hwcihowlud accompilshthistransofrmaitonbyitsmeretouchandwoludinaddiitongiveperpeutlayoutothtiofsutrnaet possessor.Noonehaseverofundsuchastone,andnoonehassucceededinchangingonemetlainot anothe.r Number of elements.thgietuylotnisbo—agearrebsfotsbuecnaheTumntoebeelemtnssnowconsidered ina.llManyofthesearerare,andveryefwofthemmakeanylargefraitconofhtemaetirlasintheeatr'hs cruts.Clakregivesthefololwingesitmaetofthecompostiionoftheearth'scrus:t Oxygen47.0%Caclium35.% Sicilon279.Magneisum2.5 Aluminium81.Sodium27. rI on 4.7 Potassium 2.4 Othereelmestn12.% AcompeltetsiloftheelemetnsisvigeninhteAppendix.Inthislsithtemorecommonofhteleemetnsare markedwithanasterisk.Itsinotnecessarotyutsdymorethanahtirdohtfeotatlnumberofeelmetnsotgian avegyroodknowledgeofchemisyrt. Physcialstateoftheelements.Abouttsenreaasgaesnetfoehtmeleres.ratuTwoidantromeepyrt—mercuyrandbromine—areilquid.sTheothersareallsloid,sthoughtheirmleitngpiostnvarhtyroughwide limit,sfromcæsiumwhcihmlestat26°otelemestnwcihhdonotmetlsaveintheinetnseheatoftheeeltcric furnace. Occurrenceoftheeelments.edinubsunsmbconinatssecCtirapaomfweevylhteofentselemuraocc narute,mostofthembiengfoundinhteformofchemiclacompounds.Whenaneelmetndoesoccrubytisefl, assithecasewtihgold,wesahtyattioccrusinthefseeratet onra it vehtoredenhtiwiscombiwhenit; subtsancesintheformofcompound,swesayhtattioccrusinthecdenibmoetats, orin combination.Inhte latetrcasehtereisusullailyteltabouhttecompoundtosuggesthtathteleementsipresentini;tforwehave seehtnatelemenstlosetheriownpecluiarpropertieswhentheyenetriotncombinaitonwithotherleemetn.sIt woudlneverbesuspected,ofrexamelpht,atthereddish,eatrhyl-ooikngironorecotniansiron. Namesofeelments.inatedelecenseebhvanestleme.yswatenerffidynamtaergotethgesenivehTman(1)Somenamesareveyrodlandtherioriginalmeainngsiobscrue.Suchnamesareiro,nglod,andcopper. (2)Manynameisncidaetsomertsikingphyscialproperytoftheeelmetn.Thenamebromine,forexampelsi, derivedrfomaGreekwordmeainngastench,reefrringtotheextremyleunlpeasatnodorofthesubstance. Thenameiodinecomesrfomawordmeainngviolet,alluidngothtebeatufilucoolrofiodinevapo.r(3)Some namesindicateprominetnchemiclapropertiesofhteeelmenst.Thus,nitrogenmeanstheproducerofetin,r rtinogenbiengacontsiutentofnetirorslatpeter.Hydrogenmeanswaetrforme,rsiginfiyngistpresencein water.Argonmeanslazyorinetr,hteelementbiengsonamedbecauseoifistnactivity.(4)Otherleemenst arenamedfromcouirtnesoolrcailites,asgermainumandscanidum. Symbosl.tisincpoundsidnicmotnsofnunngesamucslohottesuevnoneinamne,leedhetngticaidninIhencechemistshaveadopetdasystemofabbreivations.Theseabbreviationsareknownassymbol,seach eelmenthaivngasiditnitcvesymbo(.l1)Someitmeshteiinitlaletetrofthenamewillsuciffeotinidcatehte eelmetn.ThusItsandsforiodine,Cforcarbon.(2)Usulaylitsinecessaryotaddsomeohtercharacetirstci lettertohtesymbo,lisnceseveralnamesmaybeignwtihthesameeltet.rThusCsatndsforcarbo,nClofr cholrine,Cdforcadmium,Ceofcrerium,Cbofrculomibum(.3)Sometimesthesymbolsianabbreviaitonof hteodlLatinname.IntihswayFe(efrrum)indciatesiro,nCc(uuprum,)copper,Au(aurum,)gdlo.Thesymbslo areinulcdedinthelsitofelemenstgvienintheAppendix.Theywllibecomefamiliartrhoughconsattnuse. Chemicalaffinitythecauseofchemcialcombination.nietocombbstancesussesuachcihwcyenageThandwihchhlodsthemtogetherwhecnomibnediscalledcfinilaftyimacehThe.indberishitemirepxecsedstn chapter,howeve,rshowthatheatisotfennecessayrotbirngabotuchemicalaction.Thesiditncitonbetween thecauseproduicngchemicalacitonandhtecricumatsncesfavoringtimutsbeelcalrymade.Chemcila afifntiysialwayshtecauseofchemicalunion.Manyagenicesmaymaketiposislbeofrchemicaalfifnitytoact byovercomingcircumsatnceswihchsatndinistway.Amonghteseagenciesarehea,tligh,tandeeltccirti.yAs arlue,situloonslaopromotesatcionbetweentwosubstances.Someitmetsheseagenciesmayovecrome chemcialattractionandsooccaisonhtedecompostiionofacompound. EXERCISES 1.ngwielbg?on(hwoTodtegsloolehflassatcchanofa) The m le it ng of ice; (birgnofimkl;()thesoucht) e b ru in ng of a can ld e; (dth);(wderunpofogoinlpsoexeethasttealetWs.noimfoocesorrenumtsbqeutsoi)th
JOSEPHPRIESTLEY(Engsilh()1733-1804) Schoolt-eache,rtheologain,philosophe,rscientist; firendofBenjaminFranklin;discovererofoxygen; defender of the phlogiston theory; the first to use mercuryinapneumaitcrtough,bywhcihmeanshe frisitsoaltedingaseousformhydrochlorciacid, sulphurdioxidea,ndammonai Theevloituonoftheoxygenbeginsatabou4t00.°Ithasbeenfound,however,htatifthepotassiumcolhraetsimxiedwihtabotuonefoutrhtisweigthofmanganesedioxide,theoxygenisigvenoffatamuchlower etmperaruteJ.usthowthemanganesedioixdebirngsabotuhtsiresultisnotdefintilekynow.nTheamoutnof oxygenobiatnedrfomaigvenweigthofpotasisumcolhraetisexactlythesamewhetherhtemanganese idoxideispresenotnrot.Soafrascanbedetecetdhtemanganesedioixdeundergoesnochange.
Fig. 4 Directions for preparing oxygen.idensulltartptosaisegnrfmoateisiumchlorrennamehTxyongriparepof hteaccompaniyngdiagram(Fig.4.)Amirutxecontsisingofonepartofmanganeseidoixdeandfourpastrof poatsisumchlorateisplacedinthefalskAughthropesescanadevdveloisenygoxeTh.edatehyltnegdnahtetubeBhpemetluebteyletnodltofeotcehvorfhtaebntihieggmnooutbedbryolrecctleIth.wiastiwtilfdle andinvetredinavesselofwaet,rasshowninhteifgure.Thegarssiesinhtebottelanddsiplacesthewater.nIhtepreparaitonoflargequatnitiesofoxygen,acopperreto(trFig.5i)osfetnsubsitutetdofrhtelgassfalsk. nIhtepreparationofoxygenrfompotasisumcholraetandmanganese idoixde,themateriaslusedmustbeprue,ohterwiseaivolentexplosionmay occu.rThepruityofthematerislasietetsdbyheaitngasmallamoutnofhte mixtrueinatesttube. Thecollecitonofgases.xognitcellocrofedusdhoetmheTustratesygenill htegeneralmehtodusedforcloelcitngsuchgasesasareinsloulbeinwater orneaylrso.ThevessleC(F,4).igobeelttsaterinwhichthoctniaingntehwareinvetred,iscaleldaroticatumnep.hgu Fig.5Commercailmethodsofpreparation. Oxygen can now be purchased tsoredundergreatpressureinsrtongtseelcyilndesr(Fig.6).Itsiprepared iehterbyheatingamixtureofpoatsisumclhorateandmanganeseidoxide,orbyseparatingitfromthe nitrogenandothergaseswithwhcihtiismxiedinhteatmosphere.Themethodsemlpoyedforefeftcinghtsi separaitonwblliedescirbedinsubsequetnchapte.sr Physcialpropetries.teletasess,dorl,solrseocolsanhatervieahylthgils,sagssygOxieniar.Oneliterofi,tmeasuredatatemperatureof0°andunderapressureofone atmosphere,wieghs1.4285g.,whileunderismialrconditionosnelietrofariwieghs12.923 g.tIisbutsilghtlysuloelbinwaet.rOxygen,ilkeothergase,smaybeliqueifedbyappliyng verygreatpressureothtehiglhycoloedga.sWhenhtepressureisremovedhteilquid oxygenpassesagainiotnhtegaseoussatet,isncestibiolingpiontunderoridnayr atmosphercipressureis-1825..° Chemical properties.sreygoxpeemturaanidtyrArotst.Monosienaryvethcevitcyllacime substancesareetihernotatallafefctedbiy,torhteatcionissoslowastoescapenotcie. Atihgheretmperautre,showeve,ritsiveryactvie,andunietsdriecyltwhtimostofhte eelmenst.Thsiatcviitymaybeshownbyheaitngvairoussubtsancesunlitujsitgetindand htenbringinghteminotvesselsofthegas,whenhteywllibrunwihtgreatbrilliancy.Thusa lgowingspiltnintroduceditnoajarofoxygenbusrtsintoflame.Suplhurburnsinhteiarwith aveyrweaalfkmeandefelbeilgth;inoxyge,nhoweve,rthefalmeisincreasedinziseand birgthness.Subsatnceswhcirheadliyburninair,suchasphosphorus,bruninoxygenwith dazzlingbrillianc.yEvensubtsanceswhcihbruninariwhtigreatdifficulty,suchasrion, reaidylbruinnoxygen. Thebruningofasubatsnceinoxygensidueottherapidcombinationofthesubatsnceoorf hteleementscompoisngitwithhteoxygen.Thus,whensuplhurbrunsboththeoxygenand sulphuridsappearassuchandthereisformedacompoundohtfetwo,wcihhsianinivisbel ga,shavinghtecharatcersiticodorofbruinngsulphu.rSimlialr,yphosphorusonburning formsawihetsloidcompoundofphosphorusandoxygen,wihelironofrmsareddish-balckFig. 6 compoundofrionandoxygen. Oxidaiton.hTeetmroix da it onausehncn,esbatoracimhclegnaihwtchesaklapwceispapliedtotheche oneofistconsutitentpa,strcombineswtihoxygen.Thisprocessmayatkepalceraipld,yasihtnebruinngof phosphorus,orsolw,ylasintheoxidation(orruitsng)ofrionwhenexposedottheari.tIislaways accompainedbytheliberationofhea.tTheamountofheatilberatedbyhteoxidationofadeifnietwieghtof anyvigensubatsnceisalwayshtesame,biengenitreylindependetnofhteraipidtyofhteprocess.fIhte oixdaitonatkesalpceslowly,theheatgsieneraetdsolsowylthattisidfiifcutltodetectit.Iftheoxidationatkes lpaceraipdl,yhowever,theheatsigeneraetdinsuchashortietnvrlaofitmethatthesubstancemaybecome wihtehotorburtsiotnafalme. Combusiton;kindilngtemperature.gaterenedatsiyldiahthtteheWplackesrapesoxodiehnnattaoi sfuificentotcausethesubstanceotgolworbrutsiotnaalfmetheprocesssicalledcoinubtsmo.thratnIdeor anysubsatncemayundergocombustion,tiisnecessaryhtatitsholudbeheatedtoaceriatetnmperautre, known as theikureeratetpmnignld.tenitsiawlyasediferentbodies,buffdirfoyelidwseiraverutarepmsteThi forthesamebody.Thushtekinldingtemperautreofphosphorussifarlowerhtanhtaotrifo,nbtusideifintefor eac.hWhenanyporitonofasubstanceisheaetdulitntibeignstoburnthecombusitonwlilcontinuewithout thefurhterapcilpaitonofheat,providedtheheatgeneratedbytheprocessissfuicifetnotbringotherpartsof htesubatsncetohteikndilngtemperature.Onhteohterhand,fitheheatgeneratedisnotsfuficientto maintianhteikndilngetmperatrue,combutsionceases. Oxides.ocpmhTedixoehtfonoitafosndouybedrmclaeldanyelementareoxides.itsuonofusThniethmbco sluphru,phosphoru,sandiro,nthecompoundsofrmedarecalledrespectivyleoixdeofsulphur,oxideof phosphoru,sandoxideofiron.Ingeneral,the,nedixonaocasindompouygenfoxhnawtirletoehenemt. A greatmanysubtsancesofthisclassareknow;ninaftc,hteoxidesofllathecommonelemetnshavebeen prepared,withtheexceptioonfhtoseoffluorineandbromine.Someofthesearefamiliarcompounds.Waet,r ofrexample,sianoxideohfydrogea,nndlimeanoxideofthemetlacaclium. Productsofcombusiton.Tellacerdehcmoubtsoinfoanysubstanceapehitraalucxoresidorfdmetby produtcsofcombusitonahtfotatcnussbhuse.Teofoxidnofsulombustiohpru;siethulsurphtfocehdorptcu oixdeofrionsitheproductofhtecombuitsonofrion.Itsieivdetnhtathteproducstotfhecombustionofany subatsncemutswieghmorehtanhteoriginlasubstance,theincreaseinwieghtcorrespondingtotheamount ofoxygenatkenupintheatcofcombusito.nForexample,whenironburnshteoxideofrionformedwieghs morehtanhteoirignlario.n nIsomecasestheprodutcsofcombustionareinivislbegase,ssothathtesubtsanceundergoingcombustion isapparetnyldesrtoyed.Thu,swhenacandleburnsitsiconsumed,andsofarashteeyecanujdgenothingsi formedduirngcombutsion.Thatinvisiblegasesareofrmed,however,andthathteweigthoftheseisgreaetr htanhtewieghtofhtecandlemaybeshownbhtyeofollwingexperimen.t
Fig. 7 Alampchimneyisfilledwithscitksofhtecompoundknownassodiumhydroixde(caustic soda),andsuspendedfromhtebeamofhtebalance,asshowninFig.7A.pieceofcandleis palcedonthebaalncepansohtahttewcikcomesujtsbleowhtechimney,andhtebalancesi broughttoalevelbyadidngwiegthsottheohterpan.Thecaneldishtenligthed.The produtcsofrmedpassuprhtoughthechimneyandareabsorbedbythesodiumhydroixde. Atlhoughthecandleburnsawa,ythepanuponwhcirtihetsslsowylsink,sshowinghtatthe combustionisattendedbyanincreaseinwiegth. Combustion in air and in oxygen.,ytidiparnilyonserffdingeoyxdnirnaniaoniustiCombhteproducstformedbiengexatcylhtesame.Thattheprocessshodlutakelpaceelssraipdly inhteofrmesirreaylidundesrtood,ofrtheariisonylaboutonefifthoxyge,nhteremaining fourfitfhsbeinginertgase.sNotolnysilessoxygenavaliabel,butmuchoftheheatsi absorbedirnisianghtetemperatureofhteinergtasessurrounidngthesubtsanceundergiong combustion,andthetemperarutereachedinhtecombustionsihtereofreless. Phlogsitontheoryofcombustion.TehFercnrei471(71-3,)49chhisemLatisvogavwhoe tooxygenstinamewasthefristtoshowhtatcombuitsonsiduetounionwithoxygen. Preivouotsihitsmecombusitonwassupposedotbeduetothepresenceofasubatsnceor pirncipelclaeldpntoisoghlthowastoughtroeebmsuitocbmsenO.ecnatsbueblanthnoaerth becauseticoiatnnedmorephlogitson.Cola,ofrexamelp,washtoughtotbeveyrirchin plhogsiotn.Theashesleftafetrcombuitsonwoludnotburnbecauselalhtephlogsitonhad escaped.Ifthepholigtsoncoudlberestoredinanywa,yhtesubstancewouldthenbecome combusitbelagain.Alhtoughsihtivewseemsabsrudotusintheligthoforupresetn knowledge,tiformerylhadgenerlaacceptance.ThedsicoveyrofoxygenledLavoisierot invetsigatehtesuejb,tcandthroughhisexpeirmetnshearrviedatthetrueexpalnaitonof combusiton.Thediscoveyrofoxygenotgehterwihthtepatritplaysincombusitonsigenerally regardedatshemoitsmporatntdsicoveriynthesihotryofchemitsry.Itmarkedthedawnofa newpeirodinthegrowthofhtesicence. Combustion in the broad sense.Aethotngdiorccnevignoitinifedaobev,hterpseenceofoxygenis necessayrforcombusiton.Theetrmsisomeitmesused,however,inabroadersenseotdesignaetany chemcilachangeatetndedbyhteevoltuionofheatandligth.Thusrionandsuplhu,rorhydrogenandchlorine underceratinconitidon,swllicomibnesoraipldythatilghsitevolved,andtheacitoniscaelldacombusiton. Whenevercombutsiontakesplaceintheai,rhoweve,rhteprocesssioneofoxidatio.n Spontaneous combustion.vegichniedanoitcs,ncimealaTheterraehcmeeparutsacuh oxidaito,ndependsupontheraetatwcihhthereactionatkespalce.Thsirateisusually increasedbyraisingthetemperatrueofthesubtsancesatkingpatrintheaction. Whenalsowoixdationatkeslpaceundersuchconditionsthattheheatgeneraetdisnooltts bybiengconducetdawa,ytheetmperaruteofthesubstanceundergiongoxidationsiriased, andtihsinutrnhasetnstherateofoxidatio.nThersieintemperaturemaycoitnnueitnsihway untilthekinldingetmperatrueofhtesubsatncesireached,whencombusitonbegins. Combustionoccruirnginhtiswaysicaleldscmooesutnnaopionbust. Ceratinio,slsuchashtelinseedoliusedinpaitn,ssolwylundergooixdationatordinayr etmperatrues,andnotifnrequenylthteoirignoffireshasbeenrtacedtohtespoatnneous combusitonofioylrags.Thesponatneouscombustionohfahyabseeknnownotsetbarnson ifre.Heapsofcoalhavebeenfoundtobeonfriewhenspoatnneouscombusitonoeffredhte olnypossibleexplanaiton. Importance of oxygen.niatrecylnosmsofsrmfoeutinmAomfi.eotlailganigorivinngl.1gyxOinesestnes lpantilefcanexistwihtoutit.nIhteprocessofrespriationtheariisatkenitnohteulngswhereaceratin amountofoxygenisabsorbedbyhtebolod.tIishtencairredotallpartsofthebody,oxiidzinghteworn-otu sitsuesandchangingtheminotsubatsnceswhichmayreaidylbeileminatedfromhtebod.yTheheat generatedbyhtsioxidationisthesoruceohtfeheatofthebod.yThesmllaamoutnofoxygenwhichwaetr sidsvloefsromhteiarsupportsallthevairedformsofaquaticanimals. 2.Oxygenisasloessentialtodecay.Theprocessofdecaysirealylaikndofoixdaito,nbutitwillolnyatke lpaceinhtepresenceofcertainminetuofrmosfilfeknownasbacteria.Jutshowtheseasisstintheoxidation isnotknown.Btyihsprocessthedeadprodutcsofanimalandvegetaelbefilwihchcollectonthesufraceof hteeatrhareolswyloixdizedandsoconveretdiotnharmlesssubsatnces.Inhtsiwayoxygenactsasagreat pfiruiyngagen.t 3.Oxygensialsousedinthetreatmetnofceratindiseasesinwhcihhtepaitentisunabletoinhlaesuffciient airtosuppylhtenecessaraymoutnofoxyge.n OZONE Preparation.Wehnlecertcisparksarepassedtngareectehefogenoxyishguorhtnegyxoairaorpllmas converteditnoasubstanceclaeldozonediffers,whichformxogertaylopprsitnienygemasehT.seitre changecanlasobebrougthabotubycetrianchemicalprocesses.Thusfi,someipecesofphosphorusare lpacedinabottleandparitllaycoveredwihtwater,htepresenceofozonemaysoonbedeettcedinhteiar cotnianedinhtebottle.Theconveisronofoxygenitnoozonesiaettndedbyachangeinvulome,3vloumesof oxygenofrming2vloumesofozone.Ihtferesutlingozoneisheatedotabotu300,°thereversechangetakes lpace,the2voulmesofozonebeingchangedbackinot3voulmesofoxygen.tIsipossielbthattracesof ozoneeixtsinhteatmosphere,atlhoughitspresencehterehasnotbeendeifinetlyproved,hteetstsformerly usedofrstideteitconhaivngbeenshowntobeunreilaelb. Properites.sienozo,derapeprynlmoomcAsssofxogrexeecithalamixedwevewt,relbioh,sisspoenyogIt.separaethteozoneandthusobtiantiinpureofrm.Thegassoobiatnedhashtecharacetirtsciodornotcied abotueelctircalmachineswheninoperatio.nBysuejbctingittogreatpressrueandalowtemperautreht,e gascondensestoabliushilqiud,boilingat-119°.Whenunmixedwithothergasesozonesiveryexpolsive, chanigngbackintooxygenwtihhteilberaitonofheat.tIschemcialpropertiesaresimliartohtoseofoxygen excepthtattiafsirmoreactvie.Airoroxygenconatiningasmlalamoutnofozonesinowusedinpalceof oxygenincetrianmanuafctuirngprocesse.s Thedifferencebetweenoxygenandozone.howthatimentssEpxreotninegnenozoanchnixyonggio otherkindofmatetrsiehtiearddedtohteoxygenorwhtidrawnfromit.Thequesitonairseshten,Howcanwe accoutnforthedieffrenceinhtierpropetries?Itmustberememberedthatinallchangeswehavetotakeitno accountenergysllasweaamttrenasubstancewecahgnetis.yBinnghacamethgfotnuoiygrene properites.Thatoxygenandozoneconiatnfidefretnamountsofenergymaybeshowninanumberofway;s ofrexamelp,bythefacthtathteconverisonofozoneintooxygenisatetndedbtyheilberaitonofheat.The passageoftheeelcrtcispakrshtroughoxygenhasinsomewaychangedhteenergyconettnofhteleement andthusithasacqriuednewproperties.Oxragerebisadedalicntderfaosadngyneenmooztheust,re,refo asthekindofmatterofwhcihhteyarecomposedsiconcerned.Theirdifefrentproperitesaredueottheri idfferenetnergcyonetn.st Allotropcistatesorformsofmatte.rntslemedesbesireeOhtniremohatonngyxomneeyatsixeofmr. ThesedffierentformsofthesameleementarecaelldllaostateicstroporformssmseheorfenemTt.elefhtoideffrnotolnyinphysicalproperitesbtuaslointherienergycontents.Elemetnostfeentsixinavarieytofforms whciholokquitedifferent.Theseffiderencesmaybedueotaccidentalcause,ssuchastheiszeorshapeof htepaitrelcsorthewayinwhichtheeelmetnwasprepared.Onlysuchofrms,however,ashavedfiefretn energycotnenstarepropecylrlaeldlaoltropicofrms. MEASUREMENT OF GAS VOLUMES Standardconditions.ewllsanwfk-onthatactvoltheuccoemuybdeipnifideagheiwtetfoayngsacnabeitI alteredbychanigngthetemperatureofthegasorhtepressureotwcihsitihsujbecetd.Inmeasuirngthe voulmeofgasesitsihtereofrenecessary,ofrthesakeofaccruac,yotadoptsometsandardconiditonsof temperautreandpressure.Theconiditonasgreeduponare(1)aetmperatrueof0°,and(2)apressureequal tohteaveragepressureexertedbyhteatmosphereatthesealeve,lhtatsi,1033.3g.persquareceitnmeet.r Thesecondtiionsoftemperatureandpressrueareknownasthesnoiddrcitnotdaan,sand when the volume ofagassiigvenitisunderstoodhtatthemeasruementwasmadeundertheseconiditon,sulnessitsi expreslsysatetdohterwsie.Forexamlpe,hteweigthofaetilrofoxygenhasbeenigvenas1.4285g.Thsi meansthatonelietrofoxyge,nmeasuredatatemperatrueof0°andunderapressureof1033.3g.per squarecetnimeet,rwieghs14.285g. Theconidtionswhichprevaliinhtealboratoryareneverhteatsndardconditions.tIbecomesnecessary, thereofreot,ifndawaytocaclualetthevloumewhichagaswilloccupyundertsandardconditionsfromthe vloumewcihihotccuipesunderanyotherconiditon.sThsimaybedoneianccordancewiththefollowinglaw.s LawofChaelrs.situasnpogahsarutafoeffehetesssrexpewalsihTmperetenthgeihcnahahwcicet voulme.Itmaybesattedasofllows:fogaarisssevobaezetorehForeverydegreetehtmeeparuter vloumeofthegassiincreasedby12/73ofhtevolumewcihhtioccupiesatzero;likewiseforeverydegree hteetmperatureofthegasflalsbleowzerothevolumeohtfegassidecreasedby12/73ofthevolume whcihitoccuipesatzero,providedinbohtcaseshtatthepressureotwcihhhtegasissubjecetdremians consatnt. IfVebllat1°wivolumehtnetehat°0,ofeasgvheumolnesetstrperV372/1+V; at 2° ti w li l beV+ 2/273V; or,ingeneral,thevolume,vatthetemperautre,tmularofehtybdesseprexebllwi(1)v =V+ /t273V, or (2)v =V(1 +t/(3)27.) Since12/73=0.00366,theformulamaybewritetn (3v) =V(1 + 0.00366t.) SincethevlaueofVit,htugsoylluattneinevnocsio(volumeunderstis)thsoneuseadnacdridnonoit transposehteequaitonothteofllowingofrm: (4)V= (/v+10.00366t). Thefollowingprolbemwlislevreaasnlilusrtationoftheaplpciationofthsiequation. Thevulomeofagasat20°is750c.c;ifndthevolumeitwilloccupyat0°,thepressureremiainngconsattn. Inhtsicasev,57=d.an0cctmoseceb)4(noitauqe,esluvaeesthgtunitstisbu.yB=20V896c9..c0.00366×20)==57/01(+Law of Boyle.isThawlursstoehetrepabydiendaasgulovehtpuccoemionelateenbetwerssepxehrsetwcihhtisisuejbcted.tImaybesatetdasfloolw:sionaportproselytehlotomeluvoeThrevnisisagaf pressureunderwcihhtiismeasured,proivdedhteetmperatureofthegasremiansconatsnt. IfVeovshtwehulembsjseurcnpsruetoaetedrntsereepPandvrpseeristnestrusserpsieeumolvhetenwh changed topniaccroadcneiw,then,,tthaheveboawlVv:p:: :P, orVP =vp,foordserwoth.nInevigar wiegthofagashteprodutcofhtenumbersrepresentingstivulomeandthepressrueotwihchitsisubjeetcd siaconatsnt. Sincethepressrueoftheatmosphereatanypiotnsiinidcaetdbythebarometircreading,itsiconveineitnn theslotuionofhteprobelmstosubtsittuehtealettofrhtrepressuremeasuredingramspersquarecenitmeter. Theaveragereadingofhtebarometerattheseaelvlesi760mm,.whcihcorrespondsotapressureof 1033.3g.persquarecenitmeter.Theofllowingproblemwillsevreasainulltsrationoftheappcilaitonof Boyle'sla.w Agasoccuipesavulomeof500c.cinaalboratoyrwherehtebaromecirtreadingis740mm.Whatvloume woludtioccupyifhteatmosphecirpressurechangedsohtathtereaidngbecame750mm.? SubtsittuingthevlauesintheequationVP=vp, we have 500 × 740 =v7×=ro05,v393.4cc. Varaitionsinthevolumeofagasduetochangesbothintemperatureandpressure.anmscuhasIcorretcionsmutsbemadeasarlueofrbothtemperatureandpressrue,tiisconveinentotcombinehte equaitonsgivenaboveforthecorretcionsofreach,sothatthetwocorreitconsmaybemadeinone operation.Theofollwingequationsithuosbiatned: (5)Vs=vp60(7+(1/)00.3066t,) in whichVsadndcondarionsnditusagaatsrednvhettsofeumolrepresenv ,p, andtruss,ehetolve,umrep andetmperaturerespectiveylatwhcihhtegaswaascutlaylmeasured. Thefoollwingprobelmwlilsevretoilulrtsaettheapplicationofthisequaito.n Agashavingaetmperatureof20°occuipesavloumeof500cc.whensuejbcetdotapressureindicatedbyabaromertcireadingof740mm.Whavtulomewoudlsihtgasoccupyunderstandardconditions? nIthisproblemv= 500pdan,047=,ttegeveatqun,ioewbsSu.20=abothesinalueesvtehitgnitut V=s005(7×00636×02))=440)/(760(1+0.c.c.653 Varaiitonsinthevolumeofagasduetothepressureofaqueousvapor.In manycasesgasesarecellocetdoverwater,asexlpianedunderthepreparationof oxygennI.suchcasesthereispresentinthegasacetrianamountofwatervapo.r Tsihvaporexertsadefinitepressrue,wihchactsinoppoistionothteatmosphecir pressrueandwhcihhtereforemustbesubrtactedfromhtealtetrindetermininghte effecitvepressureupotnhegas.Thus,supposewewsihotdeetrminehtepressureto whichthegasinutbeAnuitlhtolewerdisedorbeisrahT.uteejbudetc)8sis(g.Fie levleofhtewaterinsideandoistudethetubeisthesame.Theatmospherepresses downuponthesafruceofhtewater(asindciatedbyhtearrows),htusforicnghtewaetr upwardwtiihnhteutbewihtapressureequlaothteatmosphercipressure.Thefllu ofcreofihtuspwardpressure,however,sinotspetnincompressinghtegaswtiihhtne tube,forsincetiiscoellcetdoverwateritcontainsacetrianamountofwatervapo.r Thiswaetrvaporexerstapressure(asincidaetdbyhtearrowwithintheutbe)in oppoisitontohteupwardpressure.Itsiialp,nhtereofre,htattheefeftcviepressure uponthegasisequaotlhteatmospheircpressurelessthepressrueexeretdbyhte aqueousvapor.Thepressrueexertedbytheaqueousvaporincreaseswiththe etmperarute.Theifgruesrepreseitnnghteexettnoftihspressrue(oftenclaledthe etnsionofaqueousvaporprethsoresuesrehAppneevnnityexpresdix.Thear)gieetnisoninmiillmeetrsofmercuyr,ujtsashteatmosphercipressruesiexpressedin millimetersofmercuyr.Represenitngthepressureoftheaqueousvaporbya,orflamu (5) becomes (6)Vs= (v p-a+0.0(1/(76))66300t.)Fig. 8 Thellofowingprobelmwillservetoilulsrtatehtemehtodofappylinghtecorreitconofrthepressrueofhte aqueousvapo.r Thevoulmeofagasmeasruedoverwaetirnalaboratorywherethetemperautreis20°andthebaromecirt reaidngis740mm.si500cc.Whatvloumewoudltihsoccupyundersatndardconitidons? Thepressureexetredbyhteaqueousvaporat20°s(eeatelbinAppendix)isequalotthepressrueexeretdby acloumnofmercury174.mm.ihniegh.tSubsttituingthevlauesof,vt,p, andaavheinrofalum)6(ew, (6)Vs50=.cc92.44=)0)266×0.30+0061()/(717.40-0(74 Adjustment of tubes before reading gas volumes.fossagoveemulinurthgnIasmeellocsenidetc graduaetdutbesorohterreceviers,overaliquidasullirtsaetdinFig.8,thereaidngsholudbetakenafter raisingorolweirnghteutbecoiatninngthegasuntilhteelvelofhteliquidinsideandotuisdehtetubeisthe same;ofrtiisonylundertheseconditionsthattheupwardpressruewithinthetubeishtesameasthe atmospheircpressrue. EXERCISES 1.atWhethsiyr).ionadictultConswrosd?looliwgnofthefmeaninguroh(.sp,epsoh,ononozlophstgi 2.moubnacCimeehttuohtiwcelapketaniostoissfongil?th 3.oitsubmo?nIshetvoetilunoofilhgtlaawysproducedbyc 4(.a) What weight of oxygen can be obtained from 100 g. of water? (b)emuluowahWovtoccupyuldthisdnre tsandardcondtiions? 5.(aW)xofothgiewtahobtabecanygeng0.m05fornideidoxcricuermof(?ebsthiouldmewulovtahW) occupuyndersatndardcondtiions? 6.thgifoahWewtthefolleachofpmuodnswonigocsecensiotyrasearepprof.l50eg?noyx(a) water; (b) mercruicoixde(;p)csatoumsihlcatore. 7.Rdecuehteofllowingvolumestoocsnnigamnieerssurprethe0°,(:nttaa) 150 c .c at 10 (;°b) 840 cc. at 273°. 8.whatAtperatemuterepar02.°isebmeluliwerutovstilnovulemAectriaehtmetdernehwmissueafosga doubeld? 9.lowingvolumesteRudectehfloontiofsrepursstsoadnacdridnostant:(peemturate,thegninnocreriamea) 200 cc. at 740 mm.; (b) 500 l. at 380 mm. 10.1ltofeighhewhwneegnoyx.fotsitahWtmeeparuter0?°ehterprusssie507m.mndahet 11.nosiditmeepfotrearaturessndpgniwollosemulovanstotoncrddaReducethefure:(anadat21°340cc.) 753 mm; (b47dmm051tna°c00ac.5). 12.2eraperpotyrasscenesiteralomhcssuiopatofighttweWha?.mat20°and750m05l.fooyxegn 13.0.$lyve$nda50eboteitcepserercundmoxidricmhcssuietaolarethstcofotapoAmussgnierp501. kliogram,cclaluaethtecostofmaterialsnecessaryofrthepreparationof50.lofoxygenfromeachofhte abovecompound.s 14.fo.g001orhlcumsiasotp.fo52gnadtaeioxisedganemantaehidewederearepioatthnpreeg.nnfooyx Whatproducstwereelftinthelfask,andhowmuchofeachwasprese?tn CHAPTER III HYDROGEN Historical.bytncebstatsuitcndsisaaezdhsilgnEehhTelemenetyhelcylraceringoogdrwenfasstir inveitsgaotrCavendsih,whoin1766obtainedtiinaprueatset,andshoweditotbedifferentrfomtheother ialfnmmalbeairsorgaseswihchhadlongbeenknow.nLavoisiegraveihttenamehydrogen,siginyfingwaetr ofrme,risnceithadbeenfoundtobeacontstiuentofwater. Occurrence.dniofnuisgoneere,osphatmtheehtnIdrhyeatsterefedintasitetec.sInhteocbmbutonlyintra siwideyldrtsiibtued,beingaconsitutentofwateraswlelasofaivilllngorgasinm,sandtheproductsderived fromhtem,suchassatrchandsugar.About10%ofhtehumanbodyishydroge.nComibnedwtihcarbon,ti ofrmshtesubatsnceswcihchonsttiutepertoleumandnatrulaga.s Itisanitneretsingaftchtatwhilehydrogeninhterfeesatetoccrusoiylnntracesontheeatr,h tioccruisnenormousquanititeishtnegaseousmatetrsurrounidngthesunandcertainother satrs. Preparationrfomwater.everalmterbyshteomtsteohsd,ontfmpitaorebancenogdrHyawmorfderaperp whicharehtefollowing. 1.eheyBtriclectent.currperataoinfooyxgen,wateriseaylispestaraideontsahsAdnineebiedaticprethnitsconstiutenst,hydrogenandoxygenb,ypassinganelectriccruretntrhoughtiunderceraticnoniditon.s 2 .la.smteatnicrenofctioheaBytnderappropriateectrianematsluctotaonwcthitehWrbnhguonit conitidon,swaetrgviesupaporitonorhtewheloofitshydrogen,itslpacebeingtakenbyhtemetal.nIthe caseofaefwohtfemetalsthsichangeoccrusatoridnayrtemperatrue.sThu,sfiabtiofsoidumisthrownon water,anatcionssieentotakepalceatonce,sfuifcietnheatbeinggeneratedotmelthtesoidum,whcihruns aboutonhtesuafrceofthewater.Thechangewihcthakesplaceconssitisnhtesidalpcementofonehalfof htehydrogenohtfewaetbryhtesoidum,andmabyerepresetnedasofllows: _ _ _ _ | hydrogen | | sodium | sodium + | hydrogen |(water) = | hydrogen |(sodium hydroxide) + hydrogen | oxygen | | oxygen | _ _ _ _ Thesodiumhydroixdeformedasiwhetisolidwihchremiansidssvloedintheundecomposedwaeta,rndmay beobtainedbyevaporatinghtesoulitonotdyrnes.sThehydrogenisevlovedasagasandmaybecoelletcd bsyuatibleapparatu.s Othermetla,ssuchasmagneisumandrion,decomposewaterrapidylb,utonlyathigheetrmperarute.sWhen tseamsipassedoverhotrion,forexample,theironcombineswtihhteoxygenofthesteam,htusidspalicng