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Water, Water Everywhere! Essential Questions: What are the properties of Water? What are Mixtures, Solutions and Suspensions? Why is water important for living things? What is the pH scale?
Water,WaterEverywhere!
EssentialQuestions:WhatarethepropertiesofWater?
WhatareMixtures,SolutionsandSuspensions?Whyiswaterimportantforlivingthings?
WhatisthepHscale?
Yourturn!
IntroductiontoWater
•Waterm
akesup70-95%oforganism
s.
•Consistsof1O
xygenatomand2H
ydrogenatom
sper1waterm
olecule.
•How
iswaterbonded?
•Becauseofitsbondingitcanholdlargemoleculeslikeproteinstogether.
•CarriessubstancesviaO
smosis.
–Servesasm
aterialtransportation–
Blood,plantsap
•Cyclesthroughthekidneysandelim
inatedoutofthebody
FiveMajorPropertiesofW
ater1.
Waterisliquidatroom
temperature
–boilingpointishighat100°C
–low
molecularw
eight–
moleculesareusuallygaseous.
•Waterresiststem
peraturechange.Becausetheboilingpointissohigh,Ittakesalotofenergytoheatw
ater.
•Waterexistsinthreephases:
–Solid(ice)
–Liquid(“w
ater”)–
Gas(vapor)
FiveMajorPropertiesofW
ater
2.Waterhasahighfreezingpoint
–Iceislessdensethanw
ater.
(Thus,icefloatsinw
ater.)
FiveMajorPropertiesofW
ater
3.Wateristheuniversalsolventforpolarandionic
molecules(itcandissolveotherliquids,solids,or
gases)–
Polar:Waterhasaslightlypositive(+)endandaslightly
negative(-)end.–
Hydrophilic:m
eans“water-loving”,m
oleculesthatinteractw
ithwater,solubleinw
ater–
Hydrophobic:m
eans“water-fearing”,insolubleinw
ater
FiveMajorPropertiesofW
ater4.W
ateriswet:
–Hydrogenbondsholdseparatew
atermolecules
together(polarareasattract)
–Slightlynegative(-)O
xygenendisattractedtotheslightlypositive(+)H
ydrogenends.
–Cohesion:attractionofw
atermolecules
toeachother.
–Adhesion:attractionofw
atermolecules
toothertypesofmolecules.
•Exam
ple:Themeniscusinagraduatedcylinder
–Capillaryaction:cohesionandadhesionacttogether,pullingupw
ateragainstgravity.•
Example:Transportationofw
aterfromtherootstotheleaves
ofatree
FiveMajorPropertiesofW
ater
5.Waterhashighsurfacetension
–waterism
oreattractedtoitself(cohesion)thantotheairaroundit
–Stickstogether(+and–attract.)
Yo
u w
ill determ
ine
factors th
at affect S
urface T
ensio
n in
you
r P
enn
y M
ini-lab
tod
ay!
http://www.youtube.com
/watch?v=_Jh1-ElbXlk&
feature=related
Mixtures,Solutions&
SuspensionsAm
ixtureisacombinationofsubstances
wherebothsubstanceskeeptheir
originalproperties.–Physicallym
ixed,notchemically
mixed.
SignsofDehydration
Mixtures,Solutions&
SuspensionsSolution:oneorm
oresubstances(solutes)aredistributedevenlyinanothersubstance(solvent),likew
ater
–Them
oresoluteinasolvent,thehighertheconcentration
–Hom
eostasis:Organism
sregulatetheconcentrationofwaterandotherim
portantsubstancesintheirbodiestomaintainacertainstable
concentrationforlifeprocesses
SignsofDehydration
Mixtures,Solutions&
SuspensionsSuspension–m
ixtureofwaterand
non-dissolvedparticles–Exam
ple:Blood–http://w
ww.youtube.com
/watch?v=PgI80U
e-AMo
SignsofDehydration
pHScale•
pH–ameasureofhow
acidicorbasicsom
ethingis.•
UsepHpaper(litm
uspaper)totest
•Acidsrangefrom
pHof0-6–
AcidsformH+ionsinw
ater–
Example:Lem
on(pH:2)
•Neutralis7–
Example:Purew
aterandblood(pH:7)
•Basesrangefrom
pHof8-14–
BasesformOH-ionsinw
ater–
Example:Am
monia(pH:12)
•Buffers–w
eakacidsandweakbases
thatreactwithstrongacidsorbasesto
preventsuddenchangesinpH.•Usedtom
aintainhomeostasis.
Homeostasis
Theabilityortendencyofanorganismtom
aintaininternalequilibrium
,orbalance,internally.
FightClubScience:NeutralizationReaction
IntheMovie,FightClub,BradPitt’sCharacterputsa
chemicalburn(usingLye,pHof13)onEdw
ardNorton’s
Character'swethand.
–Islyeanacid,abaseoraneutralsubstance?
FightClubScience:NeutralizationReaction
IntheMovie,FightClub,BradPitt’sCharacterputsa
chemicalburn(usingLye,pHof13)onEdw
ardNorton’s
Character'swethand.
–Islyeanacid,abaseoraneutralsubstance?
–Shouldheputw
aterorvinegartostoptheburn?•WhatisthepHofW
ater?•WhatisthepHofVinegar?
FightClubScience:NeutralizationReaction
IntheMovie,FightClub,BradPitt’sCharacterputsa
chemicalburn(usingLye,pHof13)onEdw
ardNorton’s
Character'swethand.
–Islyeanacid,abaseoraneutralsubstance?
–Shouldheputw
aterorvinegartostoptheburn?•WhatisthepHofW
ater?•WhatisthepHofVinegar?
PennyMinilab!
