Water Propertiesclick here for 9/page to printProperties of WaterProperties of Water• Solid water floats on liquid water•High surface tension•High surface tension• ‘Universal’ solvent• High specific heat•High heat of vaporization•High heat of vaporizationSolid Liquid GasSolid, Liquid, Gashttp://www.unit5.org/christjs/Matter%20and%20Energy/Unit%202%20PP_files/frame.htmWater Molecule• Bent moleculeCltbd•Covalent bonds•Polar• Dissolves ionic substancessubstances•In liquid phase, Liquid water moleculesqp ,the water molecules fitmoleculesmolecules fit closely togethertogether• Polar nature allows them to attract oneattract one anotherMtd t•Most dense at 4°Chttp://www.chemlin.net/news/2007/mar2007/water.htmLi idLiquid WaterWaterH2O(l) Waterhttp://www.unit5.org/christjs/Matter%20and%20Energy/Unit%202%20PP_files/frame.htmHigh Surface TensionHigh Surface Tensionhttp://www.webelements.com/nexus/node/786http://quest.nasa.gov/space/teachers/microgravity/6surf.htmlDissolution of ionic substanceDissolution of ionic substanceWater Molecule• Bent Pl•PolarSolid IceSolid IceH2O(s) Icehttp://www.unit5.org/christjs/Matter%20and%20Energy/Unit%202%20PP_files/frame.htmMolecular Structure of IceMolecular Structure of IceZumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 455http://www.unit5.org/christjs/Matter%20and%20Energy/Unit%202%20PP files/frame.htmWater ExpansionWater Expansion• Molecule shape fit together closer in liquid•Open structured crystal due to hydrogenOpen structured crystal due to hydrogen bonding of polar molecules upon freezingCrystal structure of iceCrystal structure of ice• In solid phase of water, arrangement p,gbecomes more open, less dense •Ice floats because of this•Ice floats because of this• Expansion of 9% upon freezinghttp://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htmThree hfphases of waterwaterhttp://www.cdli.ca/CITE/glaciers.htmThree Phases of Water atThree Phases of Water at Earth’s Surface• Liquid•SolidSolid• VaporEnergy captured or released upon change from one phase to anothero o e p ase to a ot eGas SteamH2O(g) Steamhttp://www.unit5.org/christjs/Matter%20and%20Energy/Unit%202%20PP_files/frame.htmGas Solid and LiquidGas, Solid and LiquidZumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 441http://www.unit5.org/christjs/Matter%20and%20Energy/Unit%202%20PP_files/frame.htmWater phases and moleculesWater phases and moleculesEvaporationEvaporation• Kinetic energy of molecules great enough to escape surfacep• Energy is taken from liquid—cools itGh h•Gaseous phase or vapor phaseWater vaporWater vaporhttp://en.wikipedia.org/wiki/Water_vaporEvaporation or Nothttp://www.geology.sdsu.edu/classes/geol351/01watercycle/watercyclefigs.htm• Air inside glass become saturated with water and no more water can evaporate from the surfacep• Outside glass is open system that is not saturatedBoilingBoilinghttp://www.chem.purdue.edu/gchelp/liquids/boil2.htmlBoilingBoilinghttp://www.deepseaimages.com/dsilibrary/showphoto.php?photo=2912&password=&sort=1&size=medium&cat=853&page=1Microscopic boilingMicroscopic boilinghttp://www.chem.purdue.edu/gchelp/liquids/boil2.htmlBoiling TemperatureBoiling Temperature• For any given pressure, there is a temperature at which water boilsp• The temperature of the water remains at that temperature until all of the water hasthat temperature until all of the water has been changed from liquid to vapor• The length of time for this to occur does not have an effect on this temperaturenot have an effect on this temperatureBoiling Temp vs PressureBoiling Temp vs.Pressure http://www.chem.purdue.edu/gchelp/liquids/boil2.htmlPressure CookerPressure Cookerhttp://www.goodmans.net/get_item_ma-6qt_maitres-806212-6-qt-cooker.htmPressure cannerPressure cannerhttp://hgic.clemson.edu/factsheets/HGIC3020.htmBoiling at less than 100 oC• Pour in hot water• Reduce PressurePressure with isyringehttp://www.micrecol.de/air2.htmlCondensationCondensation• Opposite of evaporation•Kinetic energy of molecules running intoKinetic energy of molecules running into surface of liquid and joining itHt i t•Heats environmentCondensation on GlassCondensation on Glasshttp://www.geology.sdsu.edu/classes/geol351/01watercycle/watercyclefigs.htmAtmosphereAtmosphere• Evaporation –Energy goes into airgy g– Cools remaining waterCd ti•Condensation– Energy goes from air to surface– Warms local environmentAtmosphereAtmosphere• Warm air has greater capacity for holding water in the vapor phasepp• Saturation = at capacityRlti H idittf t•Relative Humidity—percent of water contained compared to saturated amount at that temperatureWater Vapor CapacityWater Vapor Capacityhttp://www.wdtv.com/weather/images/Weather_Review/humidity.htmCondensationCondensationhttp://observe.arc.nasa.gov/nasa/earth/hydrocycle/graphics/condensation.jpgCondensation diagramCondensation diagramhttp://weatherstreet.com/weatherquestions/What_is_condensation.htmSea FogSea Foghttp://www.anythingmarine.co.uk/anything/met.htmCoastal fogCoastal foghttp://www.victoriaweather.ca/clouds.php?image=fogEnergy of Water Phase ChangeEnergy of Water Phase Change• Calorie: energy to change 1 g water 1 K or 1 oCgy g g• Also need energy to change to different state of matterstate of matter• Energy of vaporization/condensation¾540 calories per gram of water = 2256 J/g•Energy of melting/freezing•Energy of melting/freezing¾80 calories per gram= 334 J/gTemperature• Measure of hotness• Celsius¾0ofreezing point of pure water at standard¾0freezing point of pure water at standard pressure¾100oboiling point at standard pressure¾100oboiling point at standard pressure• Fahrenheit¾0owas lowest attained¾32 was his age when he performed¾32 was his age when he performed experiments¾212 is boiling point in those increments¾212 is boiling point in those incrementsTemperature• Convert with equations¾ Order of operations32)-(F95C = Parentheses first Then multiply or divideAdd or subtract last99Add or subtract last• Or use adjacent scales such as p 142 of32 C59F +=such as p. 142 of Conceptual Physical Sciencetextbook5Science textbookTemperature• Kelvin same size as degree Celsius• ‘Absolute Zero’ is 0 K¾(notice no degree symbol on K)¾(notice no degree symbol on K)•0oC = 273 K• Molecular motion ceases at absolute
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