igcse化学15年前真题考136卷0620 sms

06200620Paper32(ExtendedumrawmarkInternational ofSecondaryMARKSCHEMEfortheMay/June2010questionpaperfortheguidanceofteachersThismarkschemeispublishedasanaidtoteachersandcandidates,toindicatetherequirementsoftheexamination.ItshowsthebasisonwhichExaminerswereinstructedtoawardmarks.ItdoesnotindicatethedetailsofthediscussionsthattookceatanExaminers’meetingbeforemarkingbegan,whichwouldhaveconsideredtheacceptabilityofalternativeanswers.MarkschemesmustbereadinconjunctionwiththequestionpapersandthereportontheCIEwillnotenterintodiscussionsorcorrespondenceinconnectionwiththesemarkCIEispublishingthemarkschemesfortheMay/June2010questionpapersformostIGCSE,GCEAdvancedLevelandAdvancedSubsidiaryLevelsyllabusesandsomeOrdinaryLevelsyllabuses.PagePageMarkScheme:Teachers’IGCSE–May/June©©UCLESIn(a),(b)and(c),descriptionsofchemicalpropertiesneednotbedetailed.Ifmorethanoneanswerisgivenineachsection,markthefirstoneandignoreanythingsubsequentunlessitcontradictswhattheyhavealreadywritten.Npertiesshouldfocusonagroup1metalandnotjustmetalsinPHYSICALsoft/canbecut(withaknife)/lowdensity/light/lowmeltingpoint/(good)conductor(heatorelectricity)/shiny(whenfreshlycut)/malleable/ductile/tarnishesCHEMICALreactwithwater(not)/(very)reactive/formssaltswithhalogens/reactvigorouslywithacids(ignoreconcentration)/formskalineorbasicoxide/fixedoxidationstateoroxidationnumberorvalencyof+1/hasonevalencyorouterselectronnotformsioniccompoundsonits propertiesshouldfocusonatransitionPHYSICALhard/highdensity/dense/highmporbp/(good)conductor(heatorelectricity)/strong/malleable/ductile/silverorgreyorlustrousorshiny CHEMICALmorethanoneoxidationstateorvalency(acceptmanyoxides)/formscolouredcompoundsorions(notcolouredonitsown)/formscomplexions/behaveasacatalyst/lessreactivethangroup PHYSICALcolourlessgas/yellow notdiatomicCHEMICALmostreactivehalogen/veryreactive/formsionicfluorides/bondswithmetals/formcovalentfluorides/bondswithnon-metals/powerfuloxidant/gainsoneelectron(tobestable)/fixedoxidationstateorvalencyof–1allowdecolourisedwhenreactswithalkene)/formsFions/formsacidicoxides/formsanacidwhenreactedwithhydrogen/hydrideisacidic notbleachingagent(a)(i)enzymesareproteins/comefromlivingorganisms/biological notenzymesarelivingor(ii)carbohydrateshave2H:1O containelementsof containwater=unlesstheystatethatcarbohydratescontainwater,thisresponsescores2orcorrect-O- condsamecorrectmonomer(thismarkislostif2differentboxesare condcontinuation(i.e.bondsatboth (i)(concentrationoramountormassetc.)ofstarchdecreases(withtime) (concentrationetc.)ofstarch eszero/allstarchgone colour(intensity)indicateshowmuchstarchispresent(canbeinferred) (ii)enzymedenatured/ notenzymeskilled/don’twork/salivaPagePageMarkScheme:Teachers’IGCSE–May/June©©UCLES(a) redbrownororangeto notjustbromineyellow(notdark)/whitesolid/precipitate/goescloudy browntoyellowwithnomentionofsolid/precipitatescores=[1]Br2+Na2S2NaBr+ sulfide(ion)/sulfur(ion)loses notsodium (i) nothydrogen/not iron(II)hydroxide/ferrous 4Fe(OH)2+O2+2H2O oxidationnumberorstateorvalencyincreases/electronloss/ to notgainssacrificialprotectionorzincissacrificedzinccorrodesnotironorzinccorrodesthereforeirondoesn’tnotjustzinczincisoxidisedinpreferencetoironzincmorereactiveorelectropositivethaniron/zincformsionsmorereadilythanironorzincloseselectronsmorereadilythaniron/electronsmoveontoiron/ironiscathodeorzincisanodeany PagePageMarkScheme:Teachers’IGCSE–May/June©©UCLES(a)(i)samemolecularformula/samberofCandHatoms differentstructuralformulaor samecompound=correctformulaofbut-2-ene/methylpropene/methyl bromine/brominewater/aqueousbromine browntocolourlessnot stays bromidelosesthefirstmarkORalkalinepotassium frompurple/pinkto stays ORacidicpotassium frompurple/pinktocolourlessnot stays heat/hightemperature(temperatureneednotbestated,butifitisstateditmust500ºCor catalyst(neednotbenamed,butiftheyarenamedacceptanymetaloxidezeolite/aluminosillicates/silicon notnickel/ ifnumbersgivenmustbe acceptbutan-1-olorbutan-2-olnotbut-1-ol/but-1-anol/(a) (i)O=O/oxygen(–)oxygen/H–H/ O-H/oxygen(–)hydrogen/OH/bondbetweenhydrogenand notH-O- (i)nopollution/noCO/noCO2/nooxidesofnitrogen/onlyproducesor/nogreenhousegases/noglobalwarming doesnotuseupfossilfuels/waterisnotafiniteresource/waterisarenewablesourceofenergy/hydrogenisrenewable/availablefromelectrolysisof obtaininghydrogenfromwaterrequiresfossilfuels/storageproblems/transportproblems/limitedrangeofvehiclesavailable/gaseousnaturemeansonlyproducessmallamountofenergyperunitvolume/methaneasasourceofreformingisfinite/lackofdistribution notexpensive/anythingregardingsafety/flbility/PagePageMarkScheme:Teachers’IGCSE–May/June©©UCLES(a) Tl (ii)TlCl filter/centrifuge/decantwashtheprecipitatedrythesolid/heatthesolid(inoven)/pressbetweenfilter allthreestatedbutnotincorrectorder=[2]twooutofthreestatedinanyorder=[1](i)silverchloride/silver photography/cameras/fi/photochromiclenses/ increasedistancebetweenlampandpaperorputlampfaraway/putascreenortranslucentorsemi-opaquematerialbetweenthem/usealesspowerfulorlowvoltageordimlamp/lowertheany thaliumsulfate+ammonia+ 2TlOH+H2SO4Tl2SO4+ notbalanced=[1]incorrectformula=[0]greenprecipitateorsolid(ignoreshadesofgreenbutnotblueygreen +2OH accept (a)sodiumipensive/difficulttoobtainsodium(fromsodiumchloride)/problemsgettingelectricity/hardtoextractsodium/highenergycostsinextractionof (i)reducetemperature/reducemeltingpoint(to900/1000°C)temperatureneednotbestated,butifitisstateditmustbewithintherangebetterconductivity/solidaluminiumoxidedoesnotaluminiumoxideisinsolubleinwany O2+4e [2]ortheyburn(away)/reactwithoxygen/formcarbon hydrogenformed/aluminiumabovehydrogeninreactivityseries/H+inpreferencetoAl3+/aluminiumismorereactivethanhydrogen aluminiummorereactivethancarbon/carboncannotreducealuminiumoxide/aluminiumishigherthancarboninthereactivityseries/carbondoesn’taluminiumoxide/carbondoesn’tdiscealuminium comparisonisessentialformark(a) acceptallmetalcludingGroupI(lithiumis notleadaccept(ii)Mnitrite/ not(i) notreversereactionisendothermicasthequestionasksabouttheforwardcondforwardreactionfavouredbylowtemperature/reversereactionfavouredhigh secondmarkonlyscoresifexothermicis(ii)positionofequilibriumtoright/forwards/moreproducts/moreN2O4/lightercolour becausethiehassmallervolume/fewer ifthefinalanswerisbetween86–89%awardallifthefinalanswerisbetween66–67%award3marks(Mrof32musthavebeenforallotheranswersmarkscanbeawardedusingthemarkschemeasbelowandapplyingecfifnecessarynumberofmolesofO2formed=0.16/24=0.0067/0.00667or1/150numberofmolesofPb(NO3)2inthesample=0.0133/0.013or1/75massofonemoleofPb(NO3)2=331gmassoflead(II)nitrateinthesample=4.4(1)percentageoflead(II)nitrateinsample=88.3%(allow markecfinthisquestionbutnottosimpleifmassoflead(II)nitrate>5.00onlymarks1and2Ifdividesby32(not24)onlylast3markscanscore大学国际考试国际普通中等教育标记计划2010年5月/6月试卷供教师指0620 32（扩展理论），最大原始分数有表明评分开始前员会议上进行的讨论的细节，该讨论会考虑替代答案的可接受性。CIECIE正在发布大多数IGCSE、GCE高级和高级附属级别课程以及一些普通级别课程2010年5/6第2页评分方案：教师版IGCSE教学大纲文件–2010年5月/6月0620(a)、(b)(c)案并忽略后续任何内容，除非它与他们已经写的内容相。无物理、化学性质逆转标记。属性应集中于第1组金属，而不仅仅是一般金属物理柔软/可切割（）/低密度/轻//（良）导体（热或电）/有光泽（当新切）/可延展/延展性/失去光泽性或碱性氧化物/固定氧化态或氧化数或+1[1]属性应集中于过渡金属物理硬/高密度/致密/高或沸点/（良）导体（热或电）/强/可延化学超过一种氧化态或化合价（接受多种氧化物）/形成有色化合物或离子（本身不）/形成1[1]物理无色气体/气体[1]非双原子分子化学性质最活泼的卤素/非常活泼/形成离子氟化物/与金属键合/形成共价氟化物/与非金属键合/强氧化剂/获得一个电子（为了稳定）–1F氢反应时形成酸/氢化物呈酸性[1]非漂白剂2(a)(i)（催化剂）[1]ii)具有2H:1O比例[1]含有水元素[1]含有水除非他们碳水化合物含有水，否则此回答得分2或正确的-O-连接[1]cond（2）[1]cond（即两端的键淀粉（浓度或数量或质量等）减少（随着时间的推移）[1]淀粉（浓度等）[1]颜色（强度）表示存在多少淀粉（可以是推断）[1]酶变性/被破坏[1]不是酶被杀死/不起作用/唾液变性第3页评分方案：教师版教学大纲试卷–2010年5月/6月06203(a)(i)红棕色或橙色至无色，不仅仅是溴脱色（非深色）/白色固体/沉淀物/变为浑浊棕色至，没有提及固体/沉淀物分数=[1][1][1] Br2+Na2S2NaBr+Siii）寻找两个评论硫化物（离子）/硫（离子）失去电子而不是硫化钠溴接受它们[1](i)氧化而非氧化还原氢/H2而不是H氢氧化亚铁/氢氧化亚铁4Fe(OH)2+O2+2H2O4Fe(OH)3氧化数或态或化合价增加/电子损失/Fe2+Fe3+不获得氧4IGCSE20105/60620324(a)(i)的分子式/相同的C和H原子数[1]不同的结构式或结构[1]相同的化合物=[1]丁-2-烯/甲基丙烯/甲基环丙烷的正确式溴/溴水/溴水[1]棕色至无色不透明[1]保持棕色[1](VII)[1]从紫色/粉红色变为绿色/棕色[1]保持紫色或酸性锰酸钾(VII)[1]从紫色/粉红色变为无色不透明[1]保持紫色b)热/高温（温度无需说明，但如果说明则必须为500oC或以上催化剂（无需命名，但如果命名，则接受任何金属氧化物或沸石/铝硅酸盐/二氧化硅）[1]/铂c)(1,2)二溴丁烷[1]如果给出的数字必须是正确的丁烷[1]丁醇[1]接受butan-1-或butan-2-ol不接受but-1-ol/but-1-anol5(a)分馏[1]蒸馏(i)O=O/氧(–)氧/H–H/氢(–)氢O-H/氧(–)氢/OH/氢和氧之间的键[1]不是H-O-Hiii)吸热。(i)CO/CO2/无氮氧化物/仅产生蒸汽或水/无温室气体/无全球变暖[1