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ID:15624154
大小:29.12 KB
页数:46页
时间:2018-08-04
《液体表面张力的测定(determination of liquid surface tension)》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、液体表面张力的测定(Determinationofliquidsurfacetension)ExperimentfiveExperimentfive,experimentfiveExperimentfiveDeterminationofliquidsurfacetensionDeterminationofsurfacetensionofliquids-DeterminationofsurfacetensionofliquidsDeterminationofliquidsurfacetensionTwobillioneightmilliontwohundredandonethousandt
2、wohundredandfive200820120520082012052008201205LiusenioradviserLiuZizhengLiuZizhengLiuzizheng1objective(1)tomeasurethesurfacetensionofdifferentconcentrationsofethanolaqueoussolution,andcalculatethesurfaceadsorptionamountandthetransverseofethanolmoleculeSectionalarea.(2)understandthenatureofsurface
3、tensionandtherelationshipbetweensurfacetensionandadsorptioncapacity.(3)grasptheprincipleofmaximumbubblepressuremethodtodeterminethesurfacetensionandsurfaceadsorptioncapacityofsolution.2theprincipleofexperimentisthatinaliquid,theattractionofanymoleculeisbalanced.ButonthesurfaceoftheliquidMolecules
4、arenotthesame.Becausethemoleculesonthesurfacelayerareattractedbytheinnerlayermoleculesontheonehand,andontheotherhand,themoleculesareexposedtothesurfacelayerTheattractionofthegasmoleculesoutsidetheliquidisgreaterthanthatofthelatter.Therefore,onthesurfacelayerofliquidsurfaceInthiscase,eachmoleculei
5、ssubjectedtoanunbalancedforcethatisperpendiculartoandpointingtotheinteriorofthefluid.ThisattractionmakesthesurfacevisibleThemoleculespushinwardtoproducethesmallestareaoftheliquid.Inordertoincreasethesurfaceareaofliquid,itisnecessarytoresistmoleculesIncreasethepotentialenergyofamoleculebyworkingin
6、ward.SothemoleculesinthesurfacelayerarelargerthanintheliquidPotentialenergy,whichisthesurfacefreeenergy,usuallyincreasesAofthemaximumworkrequiredtoincreasethesurfaceofasquaremeterGchangeofsurfacefreeenergybyasquaremeters,knownasthesurfaceunitsurfaceenergy,anditsunitisJ-m-1;Theforceactingonthesurf
7、aceoftheliquidandtheunitlengthoftheunitthatistryingtoshrinkitiscalledsurfacetensionTheunitofforceisN.M-1.Thesurfaceenergyofaliquidunitsurfaceisequaltoitssurfacetensioninnumericalterms.Ifthesurfaceareaofliquidisincrease
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