2024年化學(xué)專業(yè)英語修訂版翻譯

01THEELEMENTSANDTHEPERIODICTABLE01元素和元素周期表Thenumberofprotonsinthenucleusofanatomisreferredtoastheatomicnumber,orprotonnumber,Z.Thenumberofelectronsinanelectricallyneutralatomisalsoequaltotheatomicnumber,Z.Thetotalmassofanatomisdeterminedverynearlybythetotalnumberofprotonsandneutronsinitsnucleus.Thistotaliscalledthemassnumber,A.Thenumberofneutronsinanatom,theneutronnumber,isgivenbythequantityA-Z.在壹種原子核中的質(zhì)子數(shù)量被稱為原子序數(shù)，或質(zhì)子數(shù)，Z。在壹種電中性原子中的電子數(shù)量也等于原子序數(shù)，Z。壹種原子的總質(zhì)量被測定是非?？拷谠雍酥匈|(zhì)子和中子的總數(shù)。這個總數(shù)被稱為質(zhì)量數(shù)，A。在壹種原子中的中子數(shù)量等于A–Z的數(shù)量。Thetermelementrefersto,apuresubstancewithatomsallofasinglekind.Tothechemistthe"kind"ofatomisspecifiedbyitsatomicnumber,sincethisisthepropertythatdeterminesitschemicalbehavior.AtpresentalltheatomsfromZ=1toZ=107areknown;thereare107chemicalelements.Eachchemicalelementhasbeengivenanameandadistinctivesymbol.FormostelementsthesymbolissimplytheabbreviatedformoftheEnglishnameconsistingofoneortwoletters,forexample:這個術(shù)語(指chemicalelement)也可以指由相似質(zhì)子數(shù)的原子構(gòu)成的純化學(xué)物質(zhì)。對化學(xué)家來說，此類原子通過原子數(shù)來闡明，由于它的性質(zhì)是決定其化學(xué)行為。目前，從Z=1到Z=107的所有原子是懂得的；有107種化學(xué)元素。每壹種化學(xué)元素起了壹種名字和獨特的象征。對于大多數(shù)元素都僅僅是壹種象征的英文名稱縮寫形式，由壹種或兩個字母構(gòu)成，例如：oxygen==Onitrogen==Nneon==Nemagnesium==Mg氧==O氮==N氖==Ne鎂==MgSomeelements,whichhavebeenknownforalongtime,havesymbolsbasedontheirLatinnames,forexample:很久以來就已經(jīng)懂得某些元素，根據(jù)他們的拉丁名字符號命名，例如：iron==Fe(ferrum)copper==Cu(cuprum)lead==Pb(plumbum)鐵==鐵(鐵)銅==銅(銅)鉛==鉛(鉛)AcompletelistingoftheelementsmaybefoundinTable1.壹種完整的元素可以在表1中被發(fā)現(xiàn)。BeginninginthelateseventeenthcenturywiththeworkofRobertBoyle,whoproposedthepresentlyacceptedconceptofanelement,numerousinvestigationsproducedaconsiderableknowledgeofthepropertiesofelementsandtheircompounds1.In1869,D.MendeleevandL.Meyer,workingindependently,proposedtheperiodiclaw.Inmodernform,thelawstatesthatthepropertiesoftheelementsareperiodicfunctionsoftheiratomicnumbers.Inotherwords,whentheelementsarelistedinorderofincreasingatomicnumber,elementshavingcloselysimilarpropertieswillfallatdefiniteintervalsalongthelist.Thusitispossibletoarrangethelistofelementsintabularformwithelementshavingsimilarpropertiesplacedinverticalcolumns2.Suchanarrangementiscalledaperiodic.早在拾七世紀(jì)末期，羅伯特波義耳就開始了這項工作，他提出了目前公認的元素的概念，大量的研究使我們對元素及其化合物的性質(zhì)有了相稱的理解。在1869年，門捷列夫和邁耶，獨立工作，提出了元素周期律。用現(xiàn)代方式，元素周期律論述了元素的特性原子序數(shù)的周期性函數(shù)。換句話說，當(dāng)按原子序數(shù)增長的次序排列元素，具有相近特性的元素將沿著列表以壹定的間隔下降。因此，將具有類似性質(zhì)的元素排成縱列，從而把元素排成表格形式是有也許的。像這樣的排列叫元素周期表。Eachhorizontalrowofelementsconstitutesaperiod.Itshouldbenotedthatthelengthsoftheperiodsvary.Thereisaveryshortperiodcontainingonly2elements,followedbytwoshortperiodsof8elementseach,andthentwolongperiodsof18elementseach.Thenextperiodincludes32elements,andthelastperiodisapparentlyincomplete.Withthisarrangement,elementsinthesameverticalcolumnhavesimilarcharacteristics.Thesecolumnsconstitutethechemicalfamiliesorgroups.Thegroupsheadedbythemembersofthetwo8-elementperiodsaredesignatedasmaingroupelements,andthemembersoftheothergroupsarecalledtransitionorinnertransitionelements.每個水平排的元素構(gòu)成壹種周期。但應(yīng)當(dāng)注意的是，周期長度會發(fā)生變化。非常短的周期只包括二元素，背面跟著兩個8個元素短周期，然後是兩個由18個元素構(gòu)成的長周期。下壹種周期包括32個元素，最終壹種周期明顯是不完整的。按照這樣的安排，在同壹垂直欄的元素有相似的特點。這些垂直欄構(gòu)成化學(xué)族。兩個8個元素的周期構(gòu)成的元素被認為是主族元素，其他族的元素被稱為過渡元素。Intheperiodictable,aheavysteppedlinedividestheelementsintometalsandnonmetals.Elementstotheleftofthisline(withtheexceptionofhydrogen)aremetals,whilethosetotherightarenonmetals.Thisdivisionisforconvenienceonly;elementsborderingtheline—themetalloids-havepropertiescharacteristicof-bothmetalsandnonmetals.Itmaybeseenthatmostoftheelements,includingallthetransitionandinnertransitionelements,aremetals.在元素周期表，階梯線將元素提成金屬和非金屬元素等。階梯線左邊的元素(除氫)是金屬，右邊的是非金屬元素等。這個分割僅為以便使用；元素分界線上的元素—準(zhǔn)金屬具有金屬和非金屬的特性。這可以看出，大部分的元素，包括所有的過渡和內(nèi)在過渡元素，是金屬。Exceptforhydrogen,agas,theelementsofgroupIAmakeupthealkalimetalfamily.Theyareveryreactivemetals,andtheyareneverfoundintheelementalstateinnature.However,theircompoundsarewidespread.Allthemembersofthealkalimetalfamily,formionshavingachargeof1+only.Incontrast,theelementsofgroupIB—copper,silver,andgold—arecomparativelyinert.Theyaresimilartothealkalimetalsinthattheyexistas1+ionsinmanyoftheircompounds.However,asischaracteristicofmosttransitionelements,theyformionshavingotherchargesaswell.除了氫氣，IA由堿金屬元素構(gòu)成。他們是非?；顫姷慕饘?，在自然界中，它們從沒有以元素態(tài)形式出現(xiàn)。然而，他們的化合物是廣泛存在的。所有的堿金屬離子僅有1+的電荷。相比之下，IB銅，銀和金是惰性的。在他們的許多化合物他們存在1+離子，這與堿金屬離子是相似的。然而，像許多過渡元素所具有的特點同樣，他們也形成具有其他電荷的離子。TheelementsofgroupIIAareknownasthealkalineearthmetals.Theircharacteristicionicchargeis2+.Thesemetals,particularlythelasttwomembersofthegroup,arealmostasreactiveasthealkalimetals.ThegroupIIBelements—zinc,cadmium,andmercuryarelessreactivethanarethoseofgroupIIA5,butaremorereactivethantheneighboringelementsofgroupIB.Thecharacteristicchargeontheirionsisalso2+.IIA的元素被稱為堿土金屬。其特點是離子電荷2+。這些金屬，尤其是最終兩個元素，幾乎具有與堿金屬同樣的反應(yīng)活性。IIB元素，鋅，鎘，汞比IIA的元素具有更少的反應(yīng)活性，不過比相鄰的IB的元素有更強的反應(yīng)活性。IB的元素離子的特性電荷也是2+。Withtheexceptionofboron,groupIIIAelementsarealsofairlyreactivemetals.Aluminumappearstobeinerttowardreactionwithair,butthisbehaviorstemsfromthefactthatthemetalformsathin,invisiblefilmofaluminumoxideonthesurface,whichprotectsthebulkofthemetalfromfurtheroxidation.ThemetalsofgroupIIIAformionsof3+charge.GroupIIIBconsistsofthemetalsscandium,yttrium,lanthanum,andactinium.除了硼、IIIA元素也是具有相稱強活性金屬。在空氣中鋁似乎惰性的，但這種行為的本源是金屬表面形成了壹層薄的、不可見的氧化鋁膜，這層膜保護大量的金屬的深入氧化。IIIA金屬離子具有3+的電荷。IIIA由金屬鈧，釔，鑭系和錒系元素構(gòu)成。GroupIVAconsistsofanonmetal,carbon,twometalloids,siliconandgermanium,andtwometals,tinandlead.EachoftheseelementsformssomecompoundswithformulaswhichindicatethatfourotheratomsarepresentpergroupIVAatom,as,forexample,carbontetrachloride,CCl4.ThegroupIVBmetals—titanium,zirconium,andhafnium—alsoformscompoundsinwhicheachgroupIVBatomiscombinedwithfourotheratoms;thesecompoundsarenonelectrolyteswhenpure.IVA元素由壹種非金屬，碳、兩個準(zhǔn)金屬，硅和鍺，和兩個金屬，錫和鉛構(gòu)成。按照配位規(guī)則，這些元素的每壹種形成某些化學(xué)物，這表明每壹種IVA原子需要四個其他原子配位，例如，四氯化碳CCl4。IVB金屬—鈦、鋯、和鉿—也形成化合物，其中每個IVB原子結(jié)合四個其他原子；這些化合物的純物質(zhì)是非電解質(zhì)。TheelementsofgroupVAincludethreenonmetals—nitrogen,phosphorus,andarsenic—andtwometals—antimonyandbismuth.AlthoughcompoundswiththeformulasN2O5,PCl5,andAsCl5exist,noneofthemisionic.Theseelementsdoformcompounds-nitrides,phosphides,andarsenides—inwhichionshavingchargesofminusthreeoccur.TheelementsofgroupVBareallmetals.Theseelementsformsuchavarietyofdifferentcompoundsthattheircharacteristicsarenoteasilygeneralized.VA元素包括三種非金屬--氮、磷、砷，和兩種金屬銻和鉍。盡管物質(zhì)N2O5，PCl5，AsCl5存在，不過其中沒有壹種是離子。這些元素能形成化合物—氮化物，磷化物，和砷化物—其中離子帶3-價的負電荷。VB的元素都是金屬。這些元素形成多種不壹樣的化合物，它們的特性不輕易歸納。Withtheexceptionofpolonium,theelementsofgroupVIAaretypicalnonmetals.Theyaresometimesknown,asthe,chalcogens,fromtheGreekwordmeaning"ashformers".Intheirbinarycompoundswithmetalstheyexistasionshavingachargeof2-.TheelementsofgroupⅦAareallnonmetalsandareknownasthehalogens.fromtheGreektermmeaning"saltformers.”Theyarethemostreactivenonmetalsandarecapableofreactingwithpracticallyallthemetalsandwithmostnonmetals,includingeachother.除了釙的元素，VIA族元素是經(jīng)典的非金屬。他們是眾所周知的硫族元素，這來自于希臘字母，詞意是“灰的發(fā)明者”。在他們與金屬離子形成的二元化合物中離子帶2-價的電荷。ⅦA族的元素都是非金屬，被稱為鹵素，來自希臘術(shù)語，意即“鹽的發(fā)明者”。他們是最具有反應(yīng)活性的非金屬，可以與所有的金屬和大多數(shù)非金屬反應(yīng)，包括互相之間的反應(yīng)。TheelementsofgroupsⅥB,ⅦB,andVIIIBareallmetals.TheyformsuchawideVarietyofcompoundsthatitisnotpracticalatthispointtopresentanyexamplesasbeingtypicalofthebehavioroftherespectivegroups.ⅥB，ⅦB，和VIIIB族元素都是金屬。它們形成了多種各樣的化合物，在這壹點上我們甚至不能舉出任何能體現(xiàn)各族元素經(jīng)典變化的例子。Theperiodicityofchemicalbehaviorisillustratedbythefactthat，excludingthefirstperiod,eachperiodbeginswithaveryreactivemetal.Successiveelementalongtheperiodshowdecreasingmetalliccharacter,eventuallybecomingnonmetals,andfinally,ingroupⅦA,averyreactivenonmetalisfound.Eachperiodendswithamemberofthenoblegasfamily.除了第壹種周期，化學(xué)行為的周期性可以用事實闡明，每壹種周期以壹種非?；顫姷慕饘匍_始。沿著周期元素顯示出了逐漸減少的金屬性，最終成為非金屬，最終，在ⅦA族，可以發(fā)現(xiàn)壹種很活潑的非金屬元素。每壹種周期的結(jié)尾是壹種稀有氣體元素。02THENONMETALELEMENTS02非金屬元素Wenotedearlierthat-nonmetalsexhibitpropertiesthataregreatlydifferentfromthoseofthemetals.Asarule,thenonmetalsarepoorconductorsofelectricity(graphiticcarbonisanexception)andheat;theyarebrittle,areoftenintenselycolored,andshowanunusuallywiderangeofmeltingandboilingpoints.Theirmolecularstructures,usuallyinvolvingordinarycovalentbonds,varyfromthesimplediatomicmoleculesofH2,Cl2,I2,andN2tothegiantmoleculesofdiamond,siliconandboron.很早我們就已經(jīng)注意到非金屬體現(xiàn)出了與金屬不壹樣樣的特性。壹般來說，非金屬是比較差的電子（石墨碳除外）和熱的導(dǎo)體；他們是易碎的，壹般具有較強的顏色，并體現(xiàn)出很寬范圍的熔點和沸點。他們的分子構(gòu)造，壹般是包括了壹般的共價鍵，從簡樸的雙原子分子的H2，Cl2，I2和N2到鉆石、硅和硼的大分子。Thenonmetalsthataregasesatroomtemperaturearethelow-molecularweightdiatomicmoleculesandthenoblegasesthatexertverysmallintermolecularforces.Asthemolecularweightincreases,weencounteraliquid(Br2)andasolid(I2)whosevaporpressuresalsoindicatesmallintermolecularforces.CertainpropertiesofafewnonmetalsarelistedinTable2.在室溫下是氣相的非金屬是低分子質(zhì)量的雙原子分子和施加了非常小的分子間作用力的稀有氣體。伴隨分子量的增大，我們碰到了壹種液體(Br2)和壹種固體(I2)，其蒸氣壓也表明小的分子間作用力。某些非金屬的某些性質(zhì)列在表2中。Table2MolecularWeightsandMeltingPointsofCertainNonmetalsDiatomicMoleculesMolecularWeightMeltingPoint°CColorH22-239.1'NoneN228-210NoneF238-223PaleyellowO232-218PaleblueCl271-102Yellow—greenBr2160-7.3Red—brownI2254113Gray—blackSimplediatomicmoleculesarenotformedbytheheaviermembersofGroupsVandVIatordinaryconditions.Thisisindirectcontrasttothefirstmembersofthesegroups,N2andO2.Thedifferencearisesbecauseofthelowerstabilityofπbondsformedfromporbitalsofthethirdandhighermainenergylevelsasopposedtothesecondmainenergylevel2.Thelargeratomicradiiandmoredenseelectroncloudsofelementsofthethirdperiodandhigherdonotallowgoodparalleloverlapofporbitalsnecessaryforastrongπbond.Thisisageneralphenomenon—strongπbondsareformedonlybetweenelementsofthesecondperiod.Thus,elementalnitrogenandoxygenformstablemoleculeswithbothσandπbonds,butothermembersoftheirgroupsformmorestablestructuresbasedonσbondsonlyatordinaryconditions.Note3thatGroupVIIelementsformdiatomicmolecules,butπbondsarenotrequiredforsaturationofvalence.壹般狀況下，V和VI族包括的更重的元素不能形成簡樸的雙原子分子。這與這兩個族中所包括的第壹種元素是直接相反的，N2和O2。差異的出現(xiàn)是由于與第二主能級相反，第三和更高主能級的p軌道形成的π鍵穩(wěn)定性較低。第三和更高周期元素的更大的原子半徑和更密的電子雲(yún)不容許壹種強的π鍵所必需的p軌道很好的平行重疊。這是壹種普遍的現(xiàn)象—強的π鍵僅僅在第二周期的元素之間形成。因此，氮和氧元素形成了具有σ和π鍵的穩(wěn)定分子，不過在壹般狀況下，這兩個族的其他元素可以形成僅僅基于σ鍵的更穩(wěn)定的構(gòu)造。需要注意的是第VII族元素形成了雙原子分子，不過π鍵不需要用于價態(tài)的飽和。Sulfurexhibitsallotropicforms.Solidsulfurexistsintwocrystallineformsandinanamorphousform.Rhombicsulfurisobtainedbycrystallizationfromasuitablesolution,suchasCS2,anditmeltsat112°C.Monoclinicsulfurisformedbycoolingmeltedsulfuranditmeltsat119°C.BothformsofcrystallinesulfurmeltintoS-gamma,whichiscomposedofS8molecules.TheS8moleculesarepuckeredringsandsurviveheatingtoabout160°C.Above160°C,theS8ringsbreakopen,andsomeofthesefragmentscombinewitheachothertoformahighlyviscousmixtureofirregularlyshapedcoils.Atarangeofhighertemperaturestheliquidsulfurbecomessoviscousthatitwillnotpourfromitscontainer.Thecoloralsochangesfromstrawyellowatsulfur'smeltingpointtoadeepreddish-brownasitbecomesmoreviscous.硫具有同素異形體。固態(tài)硫存在兩種晶形和壹種無定形的形式。斜方硫通過在合適的溶液中結(jié)晶化獲得，如CS2，在112°C時融化。單斜硫通過冷卻融化的硫獲得和單斜硫在119°C時融化。兩種形式的晶體硫融化成S-gamma，它由S8分子構(gòu)成。S8的分子起皺成環(huán)和加熱到160°C仍然存在。超過160°C，S8環(huán)被破壞，其中的某些片段互相結(jié)合形成壹種高粘度的形狀不規(guī)則的混合物。在更高的溫度范圍液態(tài)硫變得黏度很高，以致于在容器中不能倒出。伴隨變得更粘稠，其顏色也從硫熔點時的稻草黃色變成紅褐色。As4theboilingpointof444°Cisapproached,thelarge-coiledmoleculesofsulfurarepartiallydegradedandtheliquidsulfurdecreasesinviscosity.Ifthehotliquidsulfurisquenchedbypouringitintocoldwater,theamorphousformofsulfurisproduced.Thestructureofamorphoussulfurconsistsoflarge-coiledheliceswitheightsulfuratomstoeachturnofthehelix;theoverallnatureofamorphoussulfurisdescribedas3rubberybecauseitstretchesmuchlikeordinaryrubber.Inafewhourstheamorphoussulfurrevertstosmallrhombiccrystalsanditsrubberypropertydisappears.伴隨靠近444°C的沸點，硫的大的螺旋狀分子被部分降解和液態(tài)硫的黏度減少。假如把熱的液態(tài)硫倒入到冷卻水裏驟冷，就會產(chǎn)生無定形硫。無定形硫的構(gòu)造由具有8個硫原子的大的螺旋線構(gòu)成；無定形硫的總特性被描述成是有彈性的，由于它可以類似于壹般的橡膠伸張。幾種小時之內(nèi)無定形硫恢復(fù)成菱形晶體，和它的彈性性質(zhì)消失。Sulfur,animportantrawmaterialinindustrialchemistry,occursasthefreeelement,asSO2involcanicregions,asH2Sinmineralwaters,andinavarietyofsulfideoressuchasironpyriteFeS2,zincblendeZnS,galenaPbSandsuch,andincommonformationsofgypsumCaSO4?2H2O,anhydriteCaSO4,andbarytesBaSO4?2H2O.Sulfur,inoneformoranother,isusedinlargequantitiesformakingsulfuricacid,fertilizers,insecticides,andpaper.硫在工業(yè)化學(xué)中是壹種重要的原材料，它以單質(zhì)，在火山區(qū)域以SO2，在礦泉水中H2S，和多種硫化物出現(xiàn)，像黃鐵礦FeS2，閃鋅礦ZnS，方鉛礦PbS等等，尚有石膏CaSO4?2H2O，硬石膏CaSO4，以及重晶石BaSO4?2H2O等壹般形態(tài)。硫或以某種方式，用于大量制造硫酸、肥料、殺蟲劑、和紙張。SulfurintheformofSO2obtainedintheroastingofsulfideoresisrecoveredandconvertedtosulfuricacid,althoughinpreviousyearsmuchofthisSO2wasdiscardedthroughexceptionallytallsmokestacks.Fortunately,itisnoweconomicallyfavorabletorecoverthesegases,thusgreatlyreducingthistypeofatmosphericpollution.Atypicalroastingreactioninvolvesthechange:2ZnS+3O2—2ZnO+2SO2在硫化物煅燒中獲得的以SO2形式存在的硫被轉(zhuǎn)化成硫酸，盡管在過去幾年許多二氧化硫通過高煙囪排放出去。幸運的是，目前回收這些氣體的成本是較低的，從而這可以大幅度地減少大氣污染。經(jīng)典的焙燒反應(yīng)如下：2ZnS+3O2-2氧化鋅+2二氧化硫Phosphorus,below800℃consistsoftetratomicmolecules,P4.Itsmolecularstructureprovidesforacovalenceofthree,asmaybeexpectedfromthethreeunpairedpelectronsinitsatomicstructure,andeachatomisattachedtothreeothers6.Insteadofastrictlyorthogonalorientation,withthethreebonds90°toeachother,thebondanglesareonly60°.Thissupposedlystrainedstructureisstabilizedbythemutualinteractionofthefouratoms(eachatomisbondedtotheotherthree),butitischemicallythemostactiveformofphosphorus.Thisformofphosphorus,thewhitemodification,isspontaneouslycombustibleinair.Whenheatedto260°Citchangestoredphosphorus,whosestructureisobscure.Redphosphorusisstableinairbut,likeallformsofphosphorus,itshouldbehandledcarefullybecauseofitstendencytomigratetotheboneswheningested,resultinginseriousphysiologicaldamage.在低于800℃時，磷由四原子分子構(gòu)成，P4。它的分子構(gòu)造提供了三個共價，可預(yù)期三個共價是由該原子構(gòu)造中三個未成對的p電子形成的，且每個原子都與此外三個相接。不是嚴格的正交取向，即三個鍵互成90°，而是鍵角僅僅是60°。這種也許的收縮構(gòu)造通過4個原子的互相作用來穩(wěn)定（每壹種原子與其他三個原子成鍵），不過它是化學(xué)上最活躍的磷的形式。這種形式的磷、白磷，在空氣中能自發(fā)燃燒。當(dāng)加熱到260°C時，它轉(zhuǎn)變成紅磷，其構(gòu)造是不確定的。紅色是在空氣中是穩(wěn)定的，不過，就像所有形式的磷，它應(yīng)當(dāng)謹慎處理，由于當(dāng)攝取時，它傾向于遷移到骨頭，這會導(dǎo)致嚴重的生理傷害。Elementalcarbonexistsinoneoftwocrystallinestructures—diamondandgraphite.Thediamondstructure,basedontetrahedralbondingofhybridizedsp3orbitals,isencounteredamongGroupIVelements.Wemayexpectthatasthebondlengthincreases,thehardnessofthediamond-typecrystaldecreases.Althoughthetetrahedralstructurepersistsamongtheelementsinthisgroup—carbon,silicon,germanium,andgraytin—theinteratomicdistancesincreasefrom1.54Aforcarbonto2.80Aforgraytin.Consequently,thebondstrengthsamongthefourelementsrangefromverystrongtoquiteweak.Infact,graytinissosoftthatitexistsintheformofmicrocrystalsormerelyasapowder.TypicaloftheGroupIVdiamond-typecrystallineelements,itisanonconductorandshowsothernonmetallicproperties7.碳元素存在兩種晶體構(gòu)造——金剛石和石墨?；陔s化的sp3軌道四面體成鍵的金剛石構(gòu)造碰到第IV族元素。我們也許但愿鍵長增長，金剛石類型的晶體硬度減少。雖然四面體構(gòu)造的元素存在這個族-碳、硅、鍺，和灰錫-原子間的距離由碳的1.54?增長到灰錫的2.80?。因此，在這四個元素之間，鍵的強度由強變?nèi)酢嶋H上，灰錫是非常柔軟的，以致于它以微晶或粉末形式存在。碳作為經(jīng)典的第IV族金剛石型晶體的元素，它是不良導(dǎo)體，且顯示其他非金屬性質(zhì)。10ALKANES10烷烴NumberofIsomers同分異構(gòu)體的數(shù)量Thecompoundsnowassignedthegenericnamealkanearealsoreferredtoassaturatedhydrocarbonsandasparaffinhydrocarbons.Thewordparaffin,fromtheLatinparumaffinis(slightaffinity)referstotheinertchemicalnatureofthesubstancesandisappliedalsotothewaxobtainablefrompetroleumandconsistingofamixtureofhigheralkanes.目前指定屬名為烷烴的化合物也被叫做飽和烷烴和鏈烷烴。石蠟壹詞,來自拉丁語“parumaffinis”(很少親和性的),指的是化學(xué)惰性的物質(zhì),并也合用于從石油和高級烷烴混合物中的得到的蠟。Derivationoftheformulasofthepentanes(3isomers),hexanes(5).andheptanes(9)hasalreadydemonstratedthesharpriseindiversitywithincreasingcarboncontent.戊烷（3個同分異構(gòu)體），已烷（5個同分異構(gòu)體），和庚烷（9個同分異構(gòu)體）的衍生物已經(jīng)表明了伴隨C含量增長，衍生物的數(shù)量會大幅度的上升。NormalAlkanes正烷烴SuccessivemembersoftheseriesdifferincompositionbytheincrementCH2andformahomologousseries.Thusheptaneandoctanearehomologoushydrocarbons;icosaneisahigherhomologofmethane.這壹系列中接連相鄰的組員間構(gòu)成不壹樣，通過增長CH2形成同系物。因此，庚烷和辛烷是同系碳氫化合物；二拾烷是甲烷的壹種較高的同系物。SaturatedUnbranched—ChainCompoundsandUnivalentRadicals飽和無支鏈的鏈狀化合物和單價基團Thefirstfoursaturatedunbranchedacyclichydrocarbonsarecalledmethane,ethane,propaneandbutane.Namesofthehighermembersofthisseriesconsistofanumericalterm,followedby"-ane"withelisionofterminal"a"fromthenumericalterm.Examplesofthesenamesareshowninthetablebelow.Thegenericnameof-saturatedacyclichydrocarbons(branchedorunbranched)is“alkane.”前四個飽和無支鏈的非環(huán)狀碳氫化合物被稱為甲烷，乙烷，丙烷和丁烷。這壹系列中更高的組員的命名包括壹種數(shù)字項，緊接著是-ane，其中數(shù)字項結(jié)尾省略了a。這些名稱的例子如下表所示。（含支鏈或非支鏈）的飽和無環(huán)碳氫化合物通用都被稱作“烷烴”。Examplesofnames:(n=totalnumberofcarbonatoms)實例名稱：(n=碳原子的總數(shù))nnn1Methane甲烷15Pentadecane拾五烷29Nonacosane二拾九烷2Ethane乙烷16Hexadecane拾六烷30Triacontane三拾烷3Propane丙烷17Heptadecane拾七烷31Hentriacontane三拾壹烷4Butane丁烷18Octadecane拾八烷32Dotriacontane三拾二烷5Pentane戊烷19Nonadecane拾九烷33Tritriacontane三拾三烷6Hexane已烷20Icosane二拾烷40Tetracontane四拾烷7Heptane庚烷21Henicosane二拾壹烷50Pentacontane五拾烷8Octane辛烷22Docosane二拾二烷60Hexacontane六拾烷9Nonane壬烷23Tricosane二拾三烷70Heptacontane七拾烷10Decane癸烷24Tetracosane二拾四烷80Octacontane八拾烷11Undecane拾壹烷25Pentacosane二拾五烷90Nonacontane九拾烷12Dodecane拾二烷26Hexacosane二拾六烷100Hectane壹百烷13Tridecane拾三烷27Heptacosane二拾七烷132Dotriacontahectane132烷14Tetradecane拾四烷28Octacosane二拾八烷SaturatedbranchedacyclichydrocarbonisnamedbyprefixingthedesignationsofthesidechainstothenameofthelongestchainwhichisnumberedfromoneendtotheotherbyArabicnumerals,thedirectionbeingsochosenastogivethelowestnumberspossibletothesidechains.Whenseriesoflocantscontainingthesamenumberoftermsarecomparedtermbyterm,thatseriesis"lowest"whichcontainsthelowestnumberontheoccasionofthefirstdifference1.Thisprincipleisappliedirrespectiveofthenatureofthesubstituents.飽和的支鏈無環(huán)烴的命名是把側(cè)鏈名稱作為最長鏈名稱的前綴，最長鏈用阿拉伯?dāng)?shù)字從壹端到另壹端進行編號，方向選擇是為了讓側(cè)鏈的編號盡量低。當(dāng)位次具有相似編號的系列被逐層比較時，直到出現(xiàn)第壹種不壹樣，最低編號的那個體系就是最低的。這壹原則合用與不考慮取代基的種類。Thepresenceofidenticalunsubstitutedradicalsisindicatedbytheappropriatemultiplyingprefixdi-,tri-,tetra-,penta-,hexa-,hepta-,octa-,nona-,deca,etc.存在相似未取代基團通過合適增長前綴二，三，四，五，六，七，，八，九，拾等來表達。Univalentradicalsderivedfromsaturatedacyclichydrocarbonsbyremovalofhydrogenfromaterminalcarbonatomarenamedbyreplacingtheending"—ane"ofthenameofthehydrocarbonby"—yl".Thecarbonatomwiththefreevalenceisnumberedas1.Asaclass,theseradicalsarecallednormal,orunbranchedchain,alkyls.單價基團是從飽和無環(huán)烴中去掉端基碳原子上的氫得來，用－yl替代烷烴名字結(jié)尾中的－ane來命名。具有自由價的碳原子編號為1。作為壹類，這些基團被稱為正烷基或非支鏈烷基。Stability.—Alkanesarerelativelyinert,chemically,sincetheyareindifferenttoreagentswhichreactreadilywithalkenesorwithalkynes.n-Hexane,forexample,isnotattackedbyconcentratedsulfuricacid,boilingnitricacid,molten"sodiumhydroxide,potassiumpermanganate,orchromicacid;withtheexceptionofsodiumhydroxide,thesereagentsallattackalkenesatroomtemperature.Thefewreactionsofwhichalkanesarecapablerequireahightemperatureorspecialcatalysis.穩(wěn)定性。烷烴在化學(xué)上是相對惰性的，由于他們和與烯烴或炔烴反應(yīng)的試劑不反應(yīng)。例如，正已烷不與濃硫酸，沸騰的硝酸，熔融的氫氧化鈉，高錳酸鉀，或鉻酸;除氫氧化鈉，這些試劑都與烯烴在室溫下反應(yīng)。少數(shù)烷烴可以參與的反應(yīng)規(guī)定較高的溫度或特殊催化。Halogenation.—Ifatesttubecontainingn-hexaneisputinadarkplaceandtreatedwithadropofbromine,theoriginalcolorwillremainundiminishedinintensityfordays.Ifthesolutionisexposedtosunlight,thecolorfadesinafewminutes.andbreathingacrossthemouthofthetubeproducesacloudofcondensaterevealinghydrogenbromideasonereactionproduct.Thereactionisaphotochemicalsubstitution:鹵化：假如把壹種裝有正已烷的試管放在黑暗的地方加壹滴溴，本來的顏色將在強度上維持不退色好幾天。假如溶液暴露在陽光下，顏色幾分鐘就消失了。試管口產(chǎn)生冷凝物，表明生成了HBr。這個反應(yīng)光是化學(xué)取代反應(yīng)：Chlorinationofalkanesismoregeneralandmoreusefulthanbrominationandcanbeeffectednotonlyphotochemicallybutalsobyothermethods.烷烴的氯化比烷烴的溴化更普遍和更有用，并且不僅可以通過光化學(xué)并且還可以通過其他措施實現(xiàn)。Lightinitiateschlorinationofanalkanebyconvertingchlorinemoleculesintochlorineatomsbyaprocessofhemolysis,inwhichacovalentbondisseveredandoneelectronisretainedbyeachoftheatomsformingthebond:Cl:Cl—→Cl?+C1?.Achlorineatomhasanodd,orunpairedelectronandisafreeradical.Becauseofthetendencyofatomstoattaintheirnormalvalenceshells,anyfreeradicalisahighlyreactivespecies.Photochemicalchlorinationproceedsthroughasuccessionoffreeradicals;itisafreeradicalchainreaction.Thechaininitiatingstep(1),hemolyticfissionofchlorinemolecules,produceschlorinefreeradicals;inchainpropagatingsteps,achlorineradicalattacksamoleculeofalkanetoproducehydrogenchlorideandanalkylradical(2),whichinturnattacksachlorinemoleculetoproduceachloroalkaneandachlorineradical(3).光引起烷烴的氯化通過均裂的形式將氯分子轉(zhuǎn)化為氯原子。其中的共價鍵斷了，每個本來形成鍵的原子分別保留壹種電子。壹種氯原子有壹種奇數(shù)的，或者未成對電子成為壹種游離基。由于原子傾向得到正常的價電子，任何游離基都是高活性的物種。光化學(xué)氯化通過游離基的傳導(dǎo)實現(xiàn)，它是游離基的鏈反應(yīng)。鏈引起環(huán)節(jié)（1），氯分子的均裂，產(chǎn)生了氯游離基;在鏈傳播環(huán)節(jié)，壹種氯游離基襲擊烷烴分子產(chǎn)生氯化氫和烷基游離基（2），而他又反過來襲擊氯分子產(chǎn)生氯代烷烴和氯游離基（3）。Sincechlorine-radicalsrequiredinstep(2)areregeneratedinstep(3),thetworeactionstogetherconstituteachainwhich,ifbothreactionsproceededwithperfectefficiency,wouldbeself-propagatingwithoutfurtherrequirementoflightenergy,Theefficiency.however.isnotperfect,forchlorineradicalscanrecombine(4),combinewithalkylradicals(5),ordissipateenergybycollisionwiththeflaskwails.Hencecontinuedradiationisrequiredtomaintainanadequatesupplyofinitiatingradicals.Thechaininitiatingsteprequiresinputoflightenergyamountingto+242.8kJ/mole.Step(2),however,isexothermic,sincetheenergyrequiredtobreaktheC—HbondislessthanthebondenergyofH—Cl.Thesecondchainpropagatingstep(3)islikewiseexothermic,andindeedchlorinationofanalkanecanproceedexplosively.由于在環(huán)節(jié)（2）中需要的氯游離基在環(huán)節(jié)（3）中再生了，這兩個反應(yīng)共同構(gòu)成鏈，假如兩個反應(yīng)均有較高的效率，反應(yīng)將是自延續(xù)的，不再需要深入的光能。然而，效率并不非常好，氯游離基可以重組（4），并結(jié)合烷基（5），或通過與瓶壁碰撞來消耗能量。因此，需要繼續(xù)輻射來維持提供充足的自由基。鏈引起環(huán)節(jié)需要投入光能達+242.8kJ/mole環(huán)節(jié)（2）然而，是放熱的，由于所需的打破C-H鍵的能量少于H—Cl鍵的能量。第二個鏈傳遞環(huán)節(jié)（3）同樣是放熱，實際上烷烴的氯化可以爆炸式的發(fā)生。Cracking.—Heatedtotemperaturesintherange500~700°,higheralkanesundergopyrolyticruptureorcrackingtomixturesofsmallermolecules,somesaturatedandsomeunsaturated.Unsaturatedhydrocarbonsproducedbyselectivecrackingofspecificpetroleumfractionsareusefulinchemicalsynthesis.Crackingrupturescarbon—carbonratherthancarbon—hydrogenbondsbecausetheenergyrequiredtobreaktheC—Cbondis247kJ/mol,whereastheC—Hbondenergyis364kJ/mol.裂解：加熱溫度在500?700℃范圍內(nèi)，高烷烴進行熱解或裂解成為小分子的混合物，包括某些飽和不飽和的。通過選擇性裂解特殊石油餾分得到的不飽和烴在化學(xué)合成上是非常有用的。裂解斷裂的碳-碳鍵而不是碳氫鍵，由于打破C-C原子鍵所需的能量是247kJ/摩爾，而打破C-H鍵的能量是364kJ/mol。Oxidation.—Thereactionofhydrocarbonswithoxygenwiththeoutputofenergyisthebasisforuseofgasolineasfuelininternalcombustionengines.TheenergyreleaseonburningagivenhydrocarbonisexpressedastheheatofcombustionintermsofkJ/mole.氧化。碳氫化合物與氧反應(yīng)放出能量是使用汽油作為內(nèi)燃機燃料的基礎(chǔ)。燃燒某壹特定的碳氫化合物所釋放的能量用燃燒熱來表達，單位是仟焦耳/摩爾。Incompletecombustionofgaseoushydrocarbonsisimportantinthemanufactureofcarbonblacks,particularlylampblack,apigmentforink,andchannelblack,usedasafillerinrubbercompounding.Naturalgasisusedbecauseofitscheapnessandavailability;theyieldofblackvarieswiththetypeofgasandthemanufacturingprocessbutusuallyisintherangeof2~6%ofthetheoreticalamount.氣態(tài)烴的不完全燃燒在工業(yè)上生產(chǎn)炭黑上很重要，尤其是燈黑，壹種墨水顏料，和槽法炭黑，用作橡膠配方的填料。天然氣的使用，由于其廉價和可實用性;黑的產(chǎn)率根據(jù)氣體種類的不壹樣以及制造工藝的不壹樣而不壹樣，但壹般是理論數(shù)額的2?6％。Partialairoxidationofamorelimitedextentisameansforproductionofspecificoxygenatedsubstances.Controlledairoxidationofhigh-boilingmineraloilsandwaxesfrompetroleumaffordsmixturesofhighercarboxylicacidssimilartothosederivedfromfatsandsuitableforuseinmakingsoaps.空氣部分氧化到壹定程度是生產(chǎn)特殊氧化物制的壹種手段，高沸點礦物油和石油中的蠟的可控空氣氧化得到了類似于來自脂肪的高級羧酸混合物，合用于制作肥皂。24VOLUMETRICANALYSIS24容量分析Generalprinciples壹般原則Chemicalanalysescanbemadebydetermininghowmuchofasolutionofknownconcentrationisneededtoreactfullywithanunknowntestsample1.Themethodisgenerallyreferredtoasvolumetricanalysisandconsistsoftitratingtheunknownsolutionwiththeone2ofknownconcentration(astandardsolution).Bytitration,youcandetermineexactlyhowmuchofareagentisrequiredtobringaboutcompletereactionofthetestsolution.Usually,completionofthereactionisindicatedbyasudden,visiblechangeinthereactionsystemthatcoincideswiththestoichiometricrelationshipbetweenmolesorequivalentsof-thereagentsolutionandthereactantinthetestsolution,Adroportwoofanappropriateindicatorsolutionproducesacolorchangeatthepointwherethereactioniscomplete-referredtoastheendpoint.化學(xué)分析是用來確定要用多少已知濃度的溶液與未知試樣完全反應(yīng)。這種措施就是壹般所說的容量分析，它用壹種已知溶液（原則溶液）標(biāo)定未知溶液。通過滴定，你能精確的懂得需要多少試劑才能導(dǎo)致（使）待測溶液完全反應(yīng)。壹般，反應(yīng)的完畢是通過在反應(yīng)體系中的忽然的可見的變化來表明的，而這種突變和試劑溶液與待測溶液中的反應(yīng)物的摩爾或當(dāng)量的化學(xué)計量關(guān)系壹致，壹兩滴合適的指示劑溶液在反應(yīng)完畢，也就是反應(yīng)終點時產(chǎn)生壹種顏色的變化。Molarityisthenumberofmoles(gram-molecularweights)ofsubstanceperliterofsolution.Themoleweightofsulfuricacidis98.08g,andtherefore,1moleofH2SO4contains98.08g.If49.04garedilutedto1liter