首页
试卷库
试题库
当前位置:
X题卡
>
所有题目
>
题目详情
在水中能形成溶液的是( )
查看本题答案
包含此试题的试卷
教案备课库《》真题及答案
点击查看
你可能感兴趣的试题
下列物质放入水中能形成溶液的是
食盐
面粉
牛奶
花生油
下列物质放入水中能形成溶液的是
石灰石
汽油
纯碱
面粉
在水中能形成无色溶液的物质是
氯化铁
木炭
蔗糖
大理石
厨房中的物质加入水中能形成溶液的是
面粉
白糖
牛奶
食用油
下列物质放入水中能形成溶液的是
面粉
牛奶
花生油
白糖
下列物质放入水中能形成溶液的是
牛奶
面粉
蔗糖
花生油
淀粉在冷水中基本没有变化但是在热水中能分散达到适当温度60~80℃时便在水中溶胀分裂形成均匀的糊状溶
将饱和FeCl3溶液分别滴入下列溶液或水中能形成胶体的是
冷水
煮沸的蒸馏水
NaOH浓溶液
NaCl浓溶液
下列物质放入水中能形成溶液的是
石灰石
汽油
食盐
面粉
下列物质放入水中能形成溶液的是
牛奶
面粉
蔗糖
花生油
下列物质放入水中能形成溶液的是
植物油
面粉
泥沙
蔗糖
下列物质分散到水中能形成溶液的是
碳酸钙
汽油
蔗糖
冰
下列物质放入水中能形成溶液的是
石蜡
面粉
蔗糖
植物油
将少量的①粉笔灰②煤油③食盐晶体④硫酸铜晶体⑤高锰酸钾晶体分别放入足量的水中充分搅拌不能形成溶液的是
下列物质放入水中能形成溶液的是
面粉
牛奶
白糖
植物油
下列物质放入水中能形成溶液的是
蔗糖
泥沙
植物油
牛奶
下列物质放入水中能形成溶液的是
面粉
牛奶
食盐
植物油
下列物质放入水中能形成溶液的是
泥沙
面粉
蔗糖
汽油
下列物质分别放入水中能形成溶液的是
牛奶
面粉
植物油
蔗糖
下列物质放在水中能形成溶液的是
面粉
花生油
白糖
牛奶
热门试题
更多
用数字12346组成没有重复数字的五位数其中偶数的个数为
三氯生X是一种广谱抗菌化合物.广泛添加于肥皂洗手液牙膏洗洁精化妆品沐浴露等个人护理用品中.三氯生的合成路线如图 1E的系统命名为.反应②的反应类型为.F分子中含饭官能团的名称是. 2已知D中不含有氯元素则D的结构简式为. 3反应①的化学方程式为. 4下列有关三氯生X的说法正确的是. A.分子中有7个原子位于同一直线上B.可与水以任意比互溶 C.能与FeCl3溶液发生显色反应D.苯环上的一溴代物有2种 5写出一种满足以下条件的三氯生X的同分异构体的结构简式. ①分子结构中只有1个苯环.且苯环上有4个侧链 ②有3种类型的官能团.其中一种为酚羟基 ③核磁共振氢谱有3组峰.峰面积之比为322 6根据题设信息.设计以甲苯为原料合成的线路其他试剂任选.
Itstartedwithawomanwhowasn'tdoinganythingparticularlyawfulbutIjustfeltunhappywhenIlookedatthephoto.Icouldn'teventellyouwhatexactlythepicturewasbutIjustrememberthefeelingthatcameoverme:annoyanceandunhappiness. IthappenedagainafewweekslaterwithaphotoofacollegestudentthatIrememberasnotbeingverynice.SuddenlyIdecidedthatI'dhadenough.Idon'tneedtofollowthesepeopleonsocialmedia.WhyamIfloodingmylifewithpeoplethatmakemeunhappy?Iunfollowedher.AndthenIbegantoridmysocialmediaplatformsofpeoplewhodidn'tmakemehappy. Workingasasocialmediastrategist1finditalmostimpossibletogiveupallsocialmediaplatformsbutitalsodidn'tneedtomakemeunhappywheneverIwasonitthroughouttheday.BesidesIlikesocialmediawhenit'sahealthyspaceforme.SoinsteadoftheextremechoiceofgivingitallupIdecidedI'dfillmyfeedwiththepeopleandthingsthatimprovedmymood. Beingselectiveaboutthepeopleyousurroundyourselfwithisimportantforyourhealthandself﹣care.WhenIrealizedhowmuchbetterIfeltwhenIdidn'tseethatbloggerpostvideothatmademerollmyeyesorapicturethatbroughtmetotearsIknewIhadmadetherightdecision. NowmyfeedfillsmewithjoywhenIseemyfriendspostabouttheirphotosandblogsfromwhichIdrawinspiration.Socialmediadoesn'thavetobetheterribleplaceeveryonesaysitisbutyouhavetobewillingtomakethefirstmovetomakeitthatway. 1Howdidtheauthorfeelwhenseeingaphotoofcollegestudent? A.Embarrassed B.Confused C.Upset D.Concerned 2Howdidtheauthordealwithpeopleonsocialmedia? A.Shedidherbesttomakefriendswiththem B.Shewipedoutthosewhomadeherunhappy. C.ShewarnedthemofthedangeronSocialmedia D.Shefeltsorryfornotstayingintouchwiththem. 3Whatmightbeadvisedtodoonsocialmediaaccordingtoothetext? A.Followpeoplewhoposthappythings. B.Learntoenjoyyourfriends'posts. C.Makecommentsafteryourfriendsposts. D.Sharehappinessandsorrowwithyourfriends. 4What'sthemainideaofthetext? A.Changingmyattitudebenefitsmegreatly. B.It'stimetolimitourtimespentonsocialmedia. C.Peoplealwaysmakesmeunhappyonsocialmedia. D.Deletingpeoplefromsocialmediachangesmyfeeling.
i是虚数单位=
水系钠离子电池安全性能好价格低廉对环境友好有着巨大的市场前景.右图为某钠离子二次电池工作原理示意图电池反应为2NaFePO4F+Na3Ti2PO432Na2FePO4F+NaTi2PO43.下列说法错误的是
Bytheendoftheyeara3D﹣printedbridgewillbeputtouseinChinaforthefirsttime. Different1traditionalbridgesits2createdesigndoesn'tusereinforcedconcrete.Itismadeofanewmaterial3designtoweatherrainandsunfor4extendedperiodandthat'sdurableenoughtomeetnationalconstructionindustrystandards.Ifpartsofthebridgebecomedamagedtheycanberepaired5separate. The15﹣meter﹣longfootbridgeinShanghai6willhaveservicelifeofupto30yearswilltake35daystobuildaccordingto7itchiefarchitect.Thecomplexcurvedsurfacesofthebridgecanonlybeachievedby8use3Dprintingtechnology.Basedonlaboratorytestingitcanbearaloadof250kilogramspersquaremeter. Thisisn'tthefirsttimethata3D﹣printedbridge9makeinChina.InJulylastyearTongjiUniversityinShanghaimadetheworld'sfirsttwo3D﹣printedpedestrianbridges. 10thatpairofbridgeswasonlybuiltasademonstrationandnotforactualuse.
Thewordtoleranceiswidelyusedinliberaldemocracies自由民主.Itindicatesapositivemeaning.Politiciansurgeustobetoleranttowardsminorities.Educatorsteachustobetoleranttowardstheother.Thepressisfullofreferencestotheneedtodisplaytolerancewhenfacedwithindividualsorgroupsespousingadifferentvieworholdingadifferentreligiousbelief.Atolerantsocietyisanobjectivesoughtafterbyanyonewhobelievesinthevaluesofdemocracy.Atolerantindividualisconnectedwithvirtuousqualities. Thequestionwemustaskiswhetherwehavebeenusingthewordtolerancefullyawareofitsmeaningandwhetherwehaveapplieditcorrectlytoreflectwhatwereallywishtoconvey. Thewordtolerancemeanstobearortobearwith.IfItoleratesomethingorsomeoneIbasicallysaythatIamreadytobearitorhim.Icantolerateabadsmelloranoisyneighbour.TheactoftolerationforcesmetodesistfromconveyingmyobjectiontotheexistenceofaphenomenonwhichIfinddifficulttobear.Abadsmelloranoisyneighbourisconsideredbymetobeanobjectionablephenomenon.BytoleratingeitherofthemIamnottransformingthebadsmellorthenoisyneighbourintopositivephenomena.Let'sbehonest:Idon'thaveadifferenttastewhenitcomestobadsmells.Isimplydislikeitandhopethatitdisappears.Idon'trespectthenoisyneighbour.IwouldratherhavehimstopatoncethenoiseheismakingsoIcanliveinpeace. Thesubjecttoleratingisbynaturenotequaltotheobjectbeingtolerated.IfItolerateyouIessentiallysaythatIamaboveyouandampreparedalthoughunwillinglytobearwithyourpresenceorwithyourpracticesoropinions.Thatmaybetrueinthecaseofanindividualwhoisreadytotoleratetheother.Howeverthisattitudebysuchanindividualthoughempiricallytrueishardlyavirtue.Certainlythefactthatanindividualinrealitymaymerelytoleratetheotherorhisopiniondoesnotjustifyagovernmentoranyofficialauthoritypromotingtoleranceasavirtue.Onecannottolerateanequalbeing.Trueequalityinvolvesrespectnottoleration.Torespecttheotherasadistinctivepersonishardlytotoleratehim.Thisisthetruemeaningofequality:diversityexistinginamutually﹣respectfulsocio﹣legalsetting. Atolerantattitudeinvolvesthegrantofafavournotaright.Thequestionweshouldaskourselvesiswhetherwewouldeverwishaparliamenttomakelawsconsideringusasindividualsandaspartofacollectiveentityorapermissiontopursuecertainactionsinterpretedasafavourratherthanaright?Indeedwouldweeverwishanyonetolistentoourviewsandacceptusthewaywearesimplybecauseheiskindenoughtotolerateus? 1Thefirsttwoparagraphsaremainlyintendedtoshowthat. A.toleranceisasymbolofliberaldemocracies B.democraticsocietyalwaysadvocatestolerance C.people'sunderstandingoftoleranceisone﹣sided D.tolerancecanbeappliedtomanysituations 2Theexampleofabadsmellandanoisyneighbourisraisedtoindicatethat. A.thewriterarefedupwiththem B.mostpeoplefindthemhardtotolerate C.thewriterisn'tprejudicedagainstthem D.toleratingthemisn'tavirtuousact 3ThemainideaofParagraph4isthat. A.toleranceshowsanunequalrelationship B.mostpeoplepromotetoleranceasavirtue C.peopleshouldshowrespectforeachother D.tolerancehasnothingtodowithrespect 4Whichcanbethebesttitleforthispassage? A.ToleranceandRespect B.WhatIstoBeTolerated? C.IsToleranceaVirtue? D.ShouldPeopleBeTolerant?
设NA为阿伏加德罗常数的值.下列说法正确的是
InthewintermonthsthetemperatureinmostofCanadausuallystaysbelow0℃.HoweverinsomepartsofCanadasuchassouthernBritishColumbiathetemperaturerarelygoesbelow0℃.Inmostareaswherepeoplelivesnowwillbeonthegroundfrommid﹣Decembertomid﹣March.ThoughCanada'swintermaybemuchcolderandlongerthanyouareusedtoitcanbeveryenjoyable.FormanyCanadiansbeingactiveinwinterisanimportantpartofenjoyinglife.Therearemanyoutdoorwinteractivitiesincludingskiingicefishingwalkingandskating.Joininginoneoftheseactivitiesmayhelpyouappreciatewinterandenjoyyourtimeoutsideinthesnow. Dressingforwinter DuringwinterinCanadayouwillneedwarmclothing.Ifpossiblearrivewiththeseitemsorbepreparedtobuythemsoonafteryourarrival.Youwillneed: ☆warmwaterproofboots☆ascarfforyourneck ☆ahatthatcoversyourears☆glovesforyourhands ☆thickwintercoatspantsandsweaters Layerskeepyouwarm It'sagoodideatolayeryourclothingbyforexamplewearingaT﹣shirtandasweaterunderneathajacket.Ifyoubecometoohotit'salwayseasiertoremoveapieceofclothingthantoaddanother.OntheWestCoastpreparetodressforcoolrainyorsnowyweather.Youwillneed: ☆awarmwaterproofcoat☆waterproofhats ☆anumbrella☆rainbootsorsnowboots LearnmoreaboutweatherandseasonsacrossCanada.YoucanalsocontactRelatedLinksforexampleanimmigrant﹣servingorganizationinthecommunitywhereyouliveformoreinformationaboutdressingforwinter. 1Whatisthemainpurposeofthefirstparagraph? A.TotellaboutthedetailsaboutCanada. B.Toshowmanyoutdoorwinteractivities. C.TointroducethedailylifeofCanadians. D.ToencourageyoutoenjoywinterinCanada. 2IfyouspendawinterinCanadayou'llpreparethefollowingEXCEPT. A.anumbrellaandsunglasses B.thickwintercoatsandpants C.waterproofhatsandcoats D.snowbootsandgloves 3Inwhichpartofanewspapercanyoufindthispassage? A.Business. B.Sports. C.Tourism. D.Health.
WhenIwasafreshmanincollegeIreceivedaletterthatforeveropenedawindowinmysoul.Ihadjuststartedwritingandthe1ofmylocalcountynewspaperhadbeenkindenoughto2someofmywork.Aboutamonthlaterthe3arrived. Hereiswhatitsaid.Youmaynot4me.Welastsaweachotherinkindergartenandmy5movedthenextyear.We6getthecountypaperinthemailthoughandwhenIsawyournameIhadtowriteyou.Youseethatfirstyearinschoolwasvery7forme.Iwasatiny8andordinary﹣lookinggirlthattheotherchildren9meeveryday.ThethingIrememberaboutyouisthatyou10did.Whenwe11togoouttheteacheralwaysputmebesideyouandyouwouldholdmyhandaswe12thestreet.Youtalkedtomeandplayedwithme.You13measapersonnotsomeonedifferentandIwillbeforever14forthat.Mywholelifewas15becauseofhowyoutreatedmeallthoseyearsago. Icarefullywrotebacktomykindergartenfriendandwe16forseveralyears17theillnessthatshehad18withsincechildhoodfinallytookherlife.IwillneverforgethoweverjusthowmuchthatsimplekindnessIhadshared19toher. Everyactofkindnesswedo20another'sheart.Everybitofgoodnesswesharemakestheworldabetterplace.Let'susethatpowerandmakebothEarthandHeavensmile. 1A.teacher B.director C.editor D.leader 2A.print B.publish C.report D.check 3A.newspaper B.message C.work D.letter 4A.remember B.recognize C.hear D.forget 5A.parents B.family C.school D.classmates 6A.still B.also C.just D.even 7A.busy B.happy C.difficult D.easy 8A.honest B.naughty C.sunny D.sick 9A.kidded B.helped C.hated D.beat 10A.occasionally B.never C.seldom D.always 11A.gotup B.linedup C.endedup D.cheeredup 12A.adventured B.visited C.cleaned D.crossed 13A.judged B.heard C.knew D.saw 14A.grateful B.hopeful C.regretful D.skillful 15A.harder B.better C.easier D.healthier 16A.cooperated B.corresponded C.lived D.worked 17A.after B.when C.before D.while 18A.experienced B.studied C.treated D.struggled 19A.meant B.done C.appeared D.got 20A.discovers B.obtains C.enriches D.touches
短周期元素XYZMN位于元素周期表中五个不同的族且原子序数依次增大其中只有N为金属元素.X元素的原子形成的阴离子的核外电子排布与氦原子相同自然界中Y元素形成的化合物的种类最多.ZM在元素周期表中处于相邻位置它们的单质在常温下均为无色气体.下列说法错误的是
氢气作为清洁能源有着广泛的应用前景含硫天然气制备氢气的流程如下. 请回答下列问题 I.转化脱硫将天然气压入吸收塔30℃时在T.F菌作用下酸性环境中脱硫过程示意图如下. 1过程i的离子反应方程式为. 2已知 ①Fe3+在pH=l.9时开始沉淀pH=3.2时沉淀完全. ②30℃时在T.F菌作用下不同pH的FeSO4溶液中Fe2+的氧化速率如下表. 在转化脱硫中请在上表中选择最佳pH范围是<pH<这样选择的原因是. Ⅱ.蒸气转化在催化剂的作用下水蒸气将CH4氧化.结合下图回答问题. 3①该过程的热化学方程式是. ②比较压强P1和p2的大小关系P1P2选填“>”“<”或“=”. ③在一定温度和一定压强下的体积可变的密闭容器中充入1molCH4和1mol的水蒸气充分反应达平衡后测得起始时混合气的密度是平衡时混合气密度的1.4倍若此时容器的体积为2L则该反应的平衡常数为结果保留2位有效数字. Ⅲ.CO变换500℃时CO进一步与水反应生成CO2和H2. Ⅳ.H2提纯将CO2和H2分离得到H2的过程如示意图 4吸收池中发生反应的离子方程式是.
甲乙丙三位同学被问到是否看过ABC三本书时甲说我看过的比乙多但没看过C书乙说我没看过B书丙说我们三人看过同一本书.由此可判断乙看过的书为
全球碳计划组织GCPTheGlobalCarbonProject报告称2018年全球碳排故盆约371亿吨.达到历史新高. 1中科院设计了一种新型的多功能复合催化荆实现了CO2直接加氢制取高辛烷值汽油其过程如图甲所示. ①已知CO2g+H2g═COg+H2Og△H=+41kJ•mol﹣1 2CO2g+6H2g═CH2=CH2g+4H2Og△H=﹣128kJ•mol﹣1 则上述过程中CO转化为CH2=CH2的热化学方程式是. ②下列有关CO2转化为汽油的说法正确的是. A.该过程中CO2转化为汽油的转化率高达78% B.在Na﹣Fe3O4上发生的反应为CO2+H2=CO+H2O C.中间产物Fe5C2的生成是实现CO2转化为汽油的关键 D.催化剂HZSM﹣5可以提高汽油中芳香烃的平衡产率 ③若在一容器中充入一定量的CO2和H2加入催化剂恰好完全反应且产物只生成C5以上的烷烃类物质和水.则起始时CO2和H2的物质的量之比不低于. 2研究表明.CO2和H2在一定条件下可以合成甲醇.反应方程式为 Ⅰ.CO2g+3H2g⇌CH3OHg+H2Og.一定条件下往2L恒容密闭容器中充入1.0mo1CO2和3.0molH2在不同催化剂作用下合成甲醇相同时间内CO2的转化率随温度变化如图乙所示. ①催化效果最佳的是催化剂填“A”“B”或“C“b点时v正v逆填“>”“<”或“=”. ②已知容器内的起始压强为100kPa.若图乙中c点已达平衡状态则该沮度下反应的平衡常数Kp=保留两位有效数字Kp为以分压表示的平衡常数分压=总压x物质的量分数. ③在莱催化剂作用下CO2和H2除发生反应I外还发生反应Ⅱ.CO2g+H2g⇌COg+H2Og. 维持压强不变按固定初始投料比将CO2和H2按一定流速通过该催化剂发生上述反应ⅠⅡ经过相同时间测得如下实验数据 表中实验数据表明升高温度CO2的实际转化率提高而甲醇选择性降低其原因是.
BroadBand:byClaireL.Evans.Portfolio2018﹩27 Thoughoftenoutnumberedbymenwomenstayedintheboomingfieldofcomputing.InthisinspiringtalewriterEvansrecordsthecontributionsofsomeofthemanywomenwhoaidedtheriseofthemodernInternet. MemorablecharactersincludeElizabethJakeFeinleraninformationscientistwhohelpedresearchersnavigatetheArpaneandStacyHornwhostartedoneofthefirstsocialnetworksEcho. TheWizardandtheProphet:byCharlesC.Mann.Knopf2018﹩28.95 Thehumanpopulationismovingtoward10billion﹣﹣﹣someexpertsthinkwe'llnearlyhitthatmarkby2050.Howwilltheearthfeedhouseandotherwisesupportsuchacrowd?Environmentalthinkersusuallyfallintooneoftwocamps:thosewhopreferconservationandcontrollingconsumptionlikeWilliamVogtandthosewhotrustinnovationtosolveourproblemsNormanBorlaugforexample.WriterManncarefullyrecordsthelivesandthoughtofthefoundersofthesetwophilosophies. ALabofOne'sOwn:byPatriciaFara.OxfordUniversityPtess2018﹩24.95 InWorldWarImanywomenintheU.K.replacedtheirapronswithchemicalsuitsandsteppedintopreviouslymale﹣onlyfieldsofsciencewheretheyledwarresearchefforts.SciencehistorianFaraillustratesthelivesofmanyoftheseforgottenwomen.Althoughtheeramarkedamajorstepforwardforwomenscientistsmanyworkedforsmallwagesinanenvironmentofdiscrimination. Inthenearly100yearssincewomenhavecomealongwayFarawritesbuttheglassceilingsremainsolidandthepipelinesleaky. AtomLand:byJonButterworth.TheExperiment2018﹩19.95 Butterworthtakesreadersonanamusingjourneythroughtheunknownworldofparticle粒子physics.ThefirststopisAtomLandwhereButterworthexplainshowelectronsprotonsandneutronscometogethertobuildupeverythingweknow.Asthejourneyunfoldswelearnaboutlesser﹣knownparticles.Thankfullyourshipisequippedwithtoolssuchasmathematicalequations方程式andalaserlightthatlightsupthedarkestofconcepts. 1Whofocusesonthefutureofourearth? A.ClaireL.Evans. B.CharlesC.Mann. C.PatriciaFara. D.JonButterworth. 2Whichbookswillyouprobablyreadifyouareinterestedinwomen'scareer? A.BroadBand&AtomLand. B.TheWizardandtheProphet&AtomLand. C.BroadBand&ALabofOne'sOwn. D.ALabofOne'sOwn&AtomLand. 3What'sthepurposeofwritingthepassagesabove? A.Toclarifysomeconcepts. B.Tointroducesomefamouswriters. C.Tomakecommentsonsomebooks. D.Torecommendsomebooks.
Asnowstormhitmyneighborhoodtheotherday.Ihadrecentlyagreedtobethehouse'sgroundskeeperwhichmeantIgot1withshoveling铲theinchesofsnowthatcoveredthedriveway. Ihadstayedinthehouseduringthe2soIwasactuallyprettyhappytohead3.IshoveledforanhourorsoandIfeltmusclesinmyarmsandlegsthatIhad4usedstarttoburn.BythetimeIfinishedshovelingIwasgettingthe5Inormallygetfrombiking.TobehonestIwaspretty6tostop. AfewdayslatersomefriendsandIgotintoa7abouthowharditistoexercise.Goingtogymsisbecomingthemostannoying8ever.Notexercisinghasaneffectonourhealth.Lessthan5%ofadultsarephysically9forhalfanhouraday.Notexercisingenoughcan10diseaseslikeheartdiseasescancerobesityanddepression. Andyetshovelingsnowwasthat11.Itdidn'ttaketoomuch12becauseIwasn'tshovelingforexercisebutto13thedriveway.Peoplepaymuchmoneyforgymmembershipsandclassesto14extrafat.Sowhynot15payingthefitnessindustrytoexerciseandhelpwitheachotherwithsuchkindof16?Surelythey'rebetteroff17thatmoneyandputtingtheenergytopracticaluse. AneighborhoodcouldhaveaFacebookgroupwherepeoplecould18thingstheyneededhelpwith.Thenpeoplewhowantedtoexercisecould19.Win﹣win.Insteadofmakingitabouthelpingpeopleitcanbeframedasanewfitness20. 1A.charged B.filled C.tasked D.crowded 2A.festival B.disaster C.rush D.storm 3A.outside B.inside C.forward D.backward 4A.usually B.directly C.really D.rarely 5A.challenge B.exercise C.threat D.power 6A.lucky B.angry C.happy D.sorry 7A.party B.meeting C.discussion D.fight 8A.homework B.routine C.solution D.business 9A.strong B.healthy C.active D.sleepy 10A.bringabout B.setoff C.takedown D.livethrough 11A.difficult B.easy C.valuable D.perfect 12A.determination B.intelligence C.reputation D.confidence 13A.design B.clear C.build D.wash 14A.puton B.passdown C.pickup D.burnoff 15A.enjoy B.miss C.stop D.escape 16A.reality B.labor C.dream D.faith 17A.saving B.collecting C.donating D.achieving 18A.seek B.imagine C.post D.examine 19A.helpout B.showoff C.turnaround D.runaway 20A.lesson B.skill C.map D.style
已知F为双曲线Ca>0b>0的左焦点直线l经过点F若点Aa0B0b关于直线l对称则双曲线C的离心率为
若xy满足约束条件目标函数z=ax+y取得最大值时的最优解仅为13则a的取值范围为
ClO2是一种优良的消毒剂浓度过高时易发生分解常将其制备成NaC1O2固体以便运翰和贮存.过氧化氢法制备NaC1O2的实验装置如图甲所示. 已知①2NaClO3+H2O2+H2SO4═2ClO2↑+O2↑+Na2SO4+2H2O. ②ClO2的熔点为一59℃沸点为11℃H2O2的沸点为150℃ ③当沮度低于38℃时NaClO2饱和溶液中析出的晶体是NaC1O2•3H2O.当温度在38﹣60℃时析出NaC1O2温度高于60℃时NaC1O2分解. 请回答下列问题 1当仪器组装完毕后有同学认为关闭弹簧夹K1和K2取下X上端的玻璃塞加入一定量的水后塞上玻璃塞再打开X下端的活塞可以检查装置的气密性.请判断该方法能否检查装置气密性并说明理由 2Cl﹣对ClO2的生成有一定催化作用.反应开始时在三颈烧瓶中加入少量盐酸ClO2的生成速率会大大提高并产生微量氯气.该过程经两步反应完成将其补充完整. ①用离子方程式表示 ②H2O2+Cl2═2C1﹣+O2+2H+. 3C中将装置浸入冰水浴中的作用是. 4若实验室采用如图乙所示的装置从C中的溶液中获得NaClO2晶体.则需要在该装置的Y处增加一个设备. ①采用上述装置浓缩NaClO2溶液的操作称为. ②水浴加热的温度最好控制在℃左右填序号. A.40B.55C.70D.100 ③装置中毛细玻璃管的作用是. ④当蒸馏烧瓶中出现大量晶体后填操作.用38﹣60℃热水洗涤晶体干操后得到产品. 5产品纯度的测定称取mg产品配成250mL溶液取25.00mol•L﹣1溶液加入足量的KI和稀H2SO4充分反应后加入指示剂用cmol•L﹣1Na2S2O3标准溶液滴定至终点I2+2S2O32﹣═2I﹣+S4O62﹣平均消耗标准溶液的体积为VmL则产品中NaClO2的质量分数是%.
假设你是李华得知你的英国好友Tom通过了来华支教的申请将于今年七月到边远地区教学.请根据下面的提示给他写封电子邮件: 1.表示祝贺; 2.分析可能遇到的挑战; 3.告知提前了解当地的风俗习惯. 注意: 1.词数100左右; 2.可以适当增加细节以使行文连贯.
具有抗菌作用的白头翁素衍生物H的合成路线如图所示 已知 i.RCH2BrR﹣HC=CH﹣R' ii. iii. 以上RR′R″代表氢烷基或芳基等 1A属于芳香烃其名称是. 2D的结构简式是. 3由F生成G的反应类型是. 4由E与I2在一定条件下反应生成F的化学方程式是此反应同时生成另外一个有机副产物且与F互为同分异构体此有机副产物的结构简式是. 5下列说法正确的是选填字母序号. A.G存在顺反异构体 B.由G生成H的反应是加成反应 C.1molG最多可以与1molH2发生加成反应 D.1molF或1molH与足量NaOH溶液反应均消耗2molNaOH 6以乙烯为起始原料结合已知信息选用必要的无机试剂合成写出合成路线用结构简式表示有机物用箭头表示转化关系箭头上注明试剂和反应条件.
文中共有10处语言错误每句中最多有两处每处错误涉及一个单词的增加删除或修改. 增加:在缺词处加一个漏字符号∧并在其下面写出该加的词. 删除:把多余的词用斜线\划掉. 修改:在错的词下划一横线并在该词下面写出修改后的词. 注意:1.每处错误及其修改均仅限一词; 2.只允许修改10处多者从第11处起不计分. MyfriendLillyandIwereonthewaybacktohomefromschoolwhenwesawaboyfalloffhisbicycles.Theboylayonthegroundscreamedinpain.Werushedtohelpandfoundiftheboy'sleftlegwasbleeding.Ithappenedthatwehavelearnedsomeknowledgeaboutfirstaidbeforesoweknewhowweshoulddo.Wedialed120andcalledanambulance.WhilewaitingitItookoutmyhandkerchiefandpressedthemontothebleedingpoint.Thenwerolledtheboyontoonesidebutputhimintherecoveryposition.Westayedwithhimuntiltheambulancearrived5minuteslate.
在等比数列{an}与等差数列{bn}中a1=1b1=﹣2a2+b2=﹣3a3+b3=﹣4. 1求数列{an}与数列{bn}的通项公式 2若cn=an+bn求数列{cn}的前n项和Sn.
AprojectinGambiaisempoweringwomenandreducingdangerouswasteatthesametime. TheWasteInnovationCenterfundedbytheEuropeanUnion'sGlobalClimateChangeAllianceshowswomenintheBrikamaareahowtorecyclewasteintousefulmaterialsandproductswhichtheycanthensellinlocalmarkets. Wood﹣likewasteisrecycledintocharcoal木炭forexamplewhichcanbeusedtosupersedefirewoodandreducethenumberoftreesthatarecutdownforfirewood.Foodwasteisrecycledintocompost混合肥料tofunctionasenvironmentallyfriendlyfertilizersandplasticisturnedintomanyusefulthings. SupportedbyWasteAidUKandtheGambiaWomen'sInitiativeGWIamongotherstheprojectprovideswomenwithskillstheycanusetobecomeself﹣sufficient自给自足的.Womenlearningatthecentercomefromfivecommunitiesandsomeofthemtravelasfaras12milestolearntheseimportantskillsthatwillprovidethemwithanincomeaccordingtoTheGuardian. IsatouCeesaywhonowleadstheGWIhighlightedtheneedtofocusoneconomicequalityinhercountrytellingTheGuardianIntermsofeducationwomenaretheoneswhoarealwaysbehind.Boysarechosentogotoschool.Whenweconductourtrainingwefindwomencandoalotbutdon'tknowwhotheyareorhowtoimplement实施things. AccordingtotheWorldHealthOrganization'sCountryCooperationStrategy2008﹣2013reportthemainenvironmentalissuefacingGambiaispoorwastemanagementinurbanareas. NdeySirengBakurinexecutivedirectoroftheNationalEnvironmentAgencyhasvoicedconcernoverhealthandenvironmentalriskssuchaswaterpollutiontheincreaseofinsectsaswellasfloodingthatoccurasaresultofpoorwastemanagement. 1WhatdoestheWasteInnovationCentertrytodo? A.DeveloplocalmarketsinBrikama. B.Teachwomenhowtoinventnewthings. C.Keepwomenawayfromdangerouswaste. D.HelpwomeninBrikamabenefitfromwaste. 2WhatdoestheunderlinedwordsupersedeinParagraph2probablymean? A.Replace. B.Transform. C.Burn. D.Reserve. 3FromwhatIsatouCeesaysaidwecanlearnthatwomeninGambia. A.don'tlearnnewthingsfast B.aren'tinterestedineducation C.reallyhopeforeconomicequality D.arenotfairlytreatedinthecountry 4Whatisthewriter'spurposeofwritingthelastparagraph? A.Tosummarizethepreviousparagraphs. B.Toprovidesomeadviceforthereaders. C.Toaddsomebackgroundinformation. D.Tointroduceanewtopicfordiscussion.
ItwasapainfultimeformeforIsufferedfromanillnessandmightneverbeabletohaveachild.Asmy40thbirthdayapproachedIbeganforthefirsttimetonoticebabiesandtheirhappysmilingmotherswhereverIwent. OnenightIcametoacafetokilltheboringtime.Anelegantlydressedsightlyolderwomanwasseatednexttome. Wouldyouliketoseeapictureofmydaughter?sheaskedmehandingmeaphotoofasmilingChinesegirl.ThechildwasaboutsevenyearsoldandwaswearingaSnowWhitecostume.That'sMelanienowinthefirstgradeshesaid.Icouldhearthemotherlyprideinhervoice.She'sprettyIsaid.Ilovehercostume.ThewomanexplainedthatshefeltstronglyaboutteachingherdaughteraboutChinesecustomsandmaintainingtiestohershoes.Whatmadeyoudecidetoadopther?Iasked.Ididn'twantworktobemywholelifeshesaid. I'mnotsureifshesawthetearsinmyeyesasIrepliedIdon'teitherbutI'mafraidit'stoolate.Iwas51whenIadoptedMelanieshesaid.Andit'sthemostrewardingexcitingthingI'veeverdone. WhenmyhusbandandIreturnedfromChinawithournine﹣month﹣olddaughterMadelineinNovember2017JillwasoneofthefirstpeopleIe﹣mailed.Ididit!Iwrote.I'mamotherandshe'sbeautiful Congratulationsshewroteback.WerecentlyreconnectedonFacebookandItoldherYouchangedmylife. 1WhatcanbeinferredfromParagraph1? A.Theauthorregrettedhermarryingtooearly. B.Theauthorwasrecoveringfromaseriousdisease. C.Theauthordidn'thaveachildofherownduetosomeillness D.Theauthorhadbeeneagertobeahappymotherforalongtime. 2WhichwordscanbestdescribeJillaccordingtoParagraph3? A.Elegantandgenerous. B.Caringandconsiderate C.Friendlyanddetermined. D.Practicalandindependent 3Whatcanwelearnabouttheauthorfromthetext? A.Shewouldn'tdevoteherwholelifesimplytowork. B.SheappreciatedthepicturedrawnbyMelanie C.Herhusbandwasagainstheradopting. D.HerdreamwaseventuallyrealizedinthecompanyofJill 4Whatintheauthor'spurposeinwritingthetext? A.Tostresstheinfluenceofthekindness B.Toshowusthehiddenbeautyinourworld C.Tocallonustoadoptmorehomelesschildren D.Tosharehermeaningfuladoptionstorywithus.
Doyoulikewritingafewparagraphseverydayaboutyourexperienceshopesmemoriesorfeelings?Ifyoudon'tit'stimetomakeachangenow.Writejustafewparagraphseverydayaboutyourexperienceshopesmemoriesandfeelingsandyouwillimmediatelybegintoexperiencebenefitstoyourpersonalgrowthandpotential. Youwillgraduallybecomebetteratexpressingyourself.1Howeverwhenyoubecomelazywithwordsyoufinditismoredifficulttodescribefeelingsshareexperiencesandmakeyourselfunderstood. 2Asyouwriteaboutmemoriesitislikeopeninganoldphotoalbum.Yourpenbeginstoexplorefeelingsanddetailsyouhaveforgottenanddreamsyouhaveleftbehind.Yousuddenlyrememberpeopleyouwouldliketocontactagain.Writingisanactivitythatavoidsdistraction使人分心的事longenoughforyoutoexplorethosewonderfulmomentsofthepast.Sometimestheyarefrightening3 Writingaboutdailyexperiencesandfeelingsprovidesarecordedhistorythatwillinfluencehowyoumakefuturedecisions4Theylearnedfromwhathadhappenedbefore.Yourhistoryisimportant.Don'tletitbeforgotten. Writingremindsyouofyourdreamsandkeepsyoumovingtowardthem.Itisameansofkeepingtrackofyourpurposeandthegoalsthatwillleadyoutoachievethem.5Itshowswhenyouhavebeendistractedandmayneedtogiveallyourattentionagaintoyourwriting. Writingalittleeverydaycouldprovidethematerialthatsomedaybecomesapublishedbook.WhenIwroteaboutmydepressionandmyfour﹣year﹣oldgranddaughterwhogotlostinthemountainsIneverdreameditwouldbeinabook. A.Youwillrememberthingslongforgotten. B.Writingkeepsyouenergeticandfullofimaginationallthetime. C.Sometimestheyarewonderfulandalmostalwaystheyarehelpful. D.Soonerorlateryouaresurelytobecomeagreatprofessionalwriter. E.Reviewingwhatyouhavewrittenisaperfectwaytoseeyourprogress. F.There'sareasonthatthegreatestleadersinhistorywerestudentsofhistory. G.Whenyouwritedailyyoucanalwaysbeamazedathowquicklyyourwritingskillsimprove.
假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅涉及一个单词的增加删除或修改. 增加:在缺词处加一个漏字符号∧并在其下面写出该加的词. 删除:把多余的词用斜线\划掉. 修改:在错的词下划一横线并在该词下面写出修改后的词. 注意:1.每处错误及其修改均仅限一词; 2.只允许修改10处多者从第11处起不计分. RecentlywehavehadainstructivediscussiononhowtomakeEnglishlearningrelaxingandinteresting.It'salltoonaturalthatwehadcomeupwithalotofadvicesconcerningthetopic.FirstlywecanhavemoreinteractiveactivitiesthatmakesEnglishlearninggreatfuninclassanditisgenerallyconsiderednotalittlebeneficiallytousall.SecondlyweneedtofindmorechancestocommunicatingwithpeopleinEnglishwhethertheyareEnglishteachersandclassmatesbecauseusingEnglishisthebestwaytolearn.Asitisknowntoallpracticemakesperfect. InmyeyestherearemanyotherwayslikelisteningEnglishsongswatchingEnglishmoviesjoiningEnglishclubsormakingpenfriendsontheInternet.Thatweneedmostismoretimeandmorespace.
假设东莞市市民使用移动支付的概率都为p且每位市民使用支付方式都相互独立的已知X是其中10位市民使用移动支付的人数且EX=6则p的值为
设1﹣im=1+ni其中mn是实数则|m﹣ni|=.
设0<p<1随机变量ξ的分布列是 则当p在01内增大时
热门题库
更多
教案备课库
教案备课库
教案备课库
教案备课库
教案备课库
教案备课库
教案备课库
教案备课库
教案备课库
高一下学期数学
教案备课库
高一上学期数学
高一上学期化学
教案备课库
教案备课库
教案备课库