液体表面张力的测定（determination of liquid surface tension）

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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