infraredspectroscopy ir lab infraredspectroscopy identificationofunknowntheuseofselectedphysicalpropertiesandinfraredspectroscopytodeterminetheidentityofanunknowncompound textmaterialsslayden pp 33 44pavia pp 851 885 infraredspectroscopy pp 941 959 massspectrometry pp 719 729 simpledistillation solomons sec 2 16 9 12 9 14lectureslides dr schornickwebsite url http classweb gmu edu jschorni irlecture ppt 4 12 2020 1 infraredspectroscopy ir lab elementsoftheexperiment1stweeklectureontheoryof infraredspectroscopymassspectroscopyultraviolet visiblespectroscopy2ndweekdeterminationofunknownphysicalpropertiesirspectrumofunknownspectroscopyproblemset willbee mailedbyinstructorduedatetobedetermined 4 12 2020 2 infraredspectroscopy ir lab physicalpropertiesofspectroscopyunknownboilingpoint purificationviasimpledistillationphysicaldescriptionofpurifiedunknownsolubilityrelativetowaterdensityrelativetowaterrefractiveindex correctedfortemperature infraredspectrumanalysisanalysisofresults identificationofunknownunknownlist slaydenmanual appendix3 p 125 127verifyphysicalpropertieswithappropriateliteraturecitation merck crc etc theliteraturecitationforacompoundmustincludetheitemnumber ifapplicable andpagenumber 4 12 2020 3 infraredspectroscopy ir lab simpledistillation backgroundnote thedistillationprocess simpleandfractional willbeformallyintroducedinalaterexperimentsimpledistillationwillbeintroducedhereaspartofthespectroscopyexperimenttopurifythesampleanddetermineitsboilingpointdistillation likespectroscopy meltingpoint refractiveindex etc isoneofthetoolsweintroduceyoutointheorganici iicoursesboilingpointandpurificationofasamplebysimpledistillationisoneofseveralphysicalproperties solubility densityrelativetowater refractiveindex meltingpoint thatyouwilldetermineroutinelyonsampleunknowns 4 12 2020 4 infraredspectroscopy ir lab simpledistillation background con t singlevaporization condensationcycleofaliquidsamplethedistillateforamixtureisalwaysimpureatanytemperaturerangebetweentherangeofboilingpointsofthecomponentstherefore itisimpossibletocompletelyseparatethecomponentsinamixturewithsimpledistillation relativelypuresubstancescanbeobtainedfromamixturewithsimpledistillation iftheboilingpointsofthecomponentsdifferbyalargeamount 100oc redistillingthedistillatefrommultiplesequentialvaporization condensationcycleswouldproduceincreasinglypuresubstances butthisisaverytediousprocess 4 12 2020 5 infraredspectroscopy ir lab simpledistillation background con t samplesofunknownorganiccompoundsthatstudentsreceiveinorganiclabaregenerallypure butmaycontainsomeimpuritiesthatcouldproduceambiguousresultswhendeterminingthechemicalorphysicalpropertiesofthecompoundsimpledistillationisusedtopurifythesamplebyseparatingthepurecompoundthatcomesoverinanarrowtemperaturerangecorrespondingtoitsboilingpointfromtheimpuritiesthathaveboilingpointslowerthanorhigherthanthecompound 4 12 2020 6 infraredspectroscopy ir lab simpledistillation basicsstepssetupsimpledistillationapparatus nextslide heatsampleandcollect inawastebeaker alldistillatethatcomesoverwhilethetemperaturecontinuestorise usuallythisinvolvesonlyasmallamount ifany ofthedistillate whenthetemperaturestabilizesoveranarrowtemperaturerangecollectthedistillateinasmallcleancontainer thebulkofthesamplewillbecollectedhere stopcollectingsamplewhenthetemperaturebeginstoriseagain i e anysampleremainingatthispointwouldconsistofimpuritieswithboilingpointsabovethatofyourunknownsample 4 12 2020 7 infraredspectroscopy ir lab typicaldistillationsetup 4 12 2020 8 infraredspectroscopy ir lab simpledistillation proceduresetupsimpledistillationapparatususe25mlor50mldistillationflaskplaceacorundumorteflonboilingchipintheflaskstartgentlewaterflowthroughcondenserputawastereceivingcontainer smallbeaker intoanicewaterbath especiallyforlowboilingliquids beginheatingsamplenote thesamplemayappeartobeboiling buttheactualboilingpointisnotreacheduntilthetemperatureoftheboilingliquidandthevaporsurroundingthethermometerbulbreachequilibrium atthispointthevaporwillstarttocondenseinthecondenser 4 12 2020 9 infraredspectroscopy ir lab simpledistillation procedurenotethetemperaturewhenthedistillatebeginstodripintothewastereceivingcontainercontinuetocollectdistillateinthewastecontaineruntilthetemperaturebeginstoleveloffremovethewastercontainerandbegincollectingthedistillateinasmallcleanerlenmeyerflasknotethetemperaturewhenyoustarttocollectthepurifiedsamplecontinuetocollectthesampleuntilthetemperaturebeginstoriseagain itmaynotchangebeforetheallofthesamplehascomeover notethetemperaturejustbeforethetemperaturebeginstochangethefirstandlasttemperaturesrecordedinthenarrowboilingrangerepresenttheboilingpointrangeofyoursample 4 12 2020 10 infraredspectroscopy ir lab solubility densityrelativetowaterplaceabout2mldistilledwaterinamediumtesttubeadd4 5dropsofthesolidorpurifiedliquidunknownshaketesttubefirmlyobservesolubilityofsampleindistilledwaterifsampleisinsoluble observewhethersample floatsontopofwaterfloatsinthemiddleofthewatersinkstothebottomofthetesttube 4 12 2020 11 infraredspectroscopy ir lab refractiveindexcleanprismsofabbe refractometerwithtissues methylalcohol begentle donottouchprismwithfingersorotherhardobjects usetissuesplace3 4dropsofsampleonprism closeprismandraiselampinfrontofprismportal flipswitchonleftsidetoturnonlight uselargedialonrighttobringlight darkimageintoview ifimagecannotbefound flipswitchonleftdownanduselargedialonrighttobringthescaleintoviewaround1 4000 4 12 2020 12 infraredspectroscopy ir lab refractiveindex con t releaseswitchonleftanduselargedialonrighttobringlight darkimageintoviewsharpenlineofdemarcationusingdrumdialonfrontofinstrument useeyepiecetosharpencross hairsalignthelineofdemarcationwiththecross hairsflipswitchonleftdownandreadvalueto4decimalplacesex 1 5523 4 12 2020 13 infraredspectroscopy ir lab thefollowingequationadjuststherawrefractiveindexvalueto20oc nd20 ndrmtemp rmtemp 20 0 00045ex foranobservedvalueof1 5523at16oc thecorrectionis nd20 1 5523 16 20 0 00045 1 5523 4 0 00045 1 5505 4 12 2020 14 refractiveindex con t infraredspectroscopy ir lab infraredspectroscopyliquidsamples1to2dropsofliquidsampleareplacedbetweentwosinglecrystalsofsodiumchloride saltplates note naclplatesarewatersoluble keepdrysolidsample