WPC/ Ci:W _BT:wh4u7 nڏ i`CDT1 jO:m+Ub;[ 9MC iݝIȅB;S9QGV[1o3G~^R4Zvb4Vgml?UVTòP]gmhi'8#D(b1ԹVvح EyN=Iѱuȟ.Ig]K8U?m[ ‚/Ԝ l0-KM&&/9jΰnYz1J >Qǀ OM' % i~yż^tWj[-Laclv3{Z:w)b7EH֟jLk@""m%Z`Hf)vIE}_y3 WN@"OС?pbX HLPYn opY_FH ?U>r 0< 0(6 0- 0%$ 0  0 0 0  0  0 0 0 0| 0^ 0@ 0 0 0 0 0 0 0e 0F 0' 0 0 0 0a Uo:! 0I4" 0@}# 0$$ 0<% 0'& 0D' 0"( 1g) 7$* 1U2* 7 *U<,* 1W* 7 + 1e"+ 7++ 0+#m,UN.. %|.M.(.N.^ . 1u. 721/wc/4g/{/ m}/\  `&Times New Roman' CHAPTER 4 susie0Giordano .   2P+M 0_level1  , 8.4 <DL!823  ..  5+ 4 <DL!5  2M+M 0_level2  X 5+4 44 <DL!523  ..  5+ 4 <DL!5  2M+M 0_level3   5+` ` ` <DL!523  ..  5+ 4 <DL!5  2J+M 0_level4   2( <DL!223  ..  5+ 4 <DL!5  2J+M 0_level5   2( <DL!223  ..  5+ 4 <DL!5  2G+M 0_level6   /% <DL!/23  ..  5+ 4 <DL!5  2G+M 0_level7  4 /% <DL!/23  ..  5+ 4 <DL!5  2D+M 0_level8  ` ,"< <<DL!,23  ..  5+ 4 <DL!5  2D+M 0_level9   ,"h hhDL!,23  ..  5+ 4 <DL!5  2PM 0_levsl1  , 8.4 <DL!823  Ԁ  5+ 4 <DL!5  2MM 0_levsl2  X 5+4 44 <DL!523  Ԁ  5+ 4 <DL!5  2MM 0_levsl3   5+` ` ` <DL!523  Ԁ  5+ 4 <DL!5  2JM 0_levsl4   2( <DL!223  Ԁ  5+ 4 <DL!5  2JM 0_levsl5   2( <DL!223  Ԁ  5+ 4 <DL!5  2GM 0_levsl6   /% <DL!/23  Ԁ  5+ 4 <DL!5  2GM 0_levsl7  4 /% <DL!/23  Ԁ  5+ 4 <DL!5  2DM 0_levsl8  ` ,"< <<DL!,23  Ԁ  5+ 4 <DL!5  2DM 0_levsl9   ,"h hhDL!,23  Ԁ  5+ 4 <DL!5  2PM 0_levnl1  , 8.4 <DL!823   5+ 4 <DL!5  2MM 0_levnl2  X 5+4 44 <DL!523   5+ 4 <DL!5  2MM 0_levnl3   5+` ` ` <DL!523   5+ 4 <DL!5  2JM 0_levnl4   2( <DL!223   5+ 4 <DL!5  2JM 0_levnl5   2( <DL!223   5+ 4 <DL!5  2GM 0_levnl6   /% <DL!/23   5+ 4 <DL!5  2GM 0_levnl7  4 /% <DL!/23   5+ 4 <DL!5  2DM 0_levnl8  ` ,"< <<DL!,23   5+ 4 <DL!5  2DM 0_levnl9   ,"h hhDL!,23   5+ 4 <DL!5  6 4Heading 1 CE    O* `"Comic Sans MSO       XXXS\  `&Times New RomanS  CE * `"Comic Sans MS6 }4Heading 2O* `"Comic Sans MSO       XXXS\  `&Times New RomanS 6 z4Heading 3O* `"Comic Sans MSO       XXXS\  `&Times New RomanS 6u l4Heading 4O* `"Comic Sans MSO   XXXS\  `&Times New RomanS<:Default Para.|} ,Title   O* `"Comic Sans MSO     XXXS\  `&Times New RomanS 6RV 4Body TextO* `"Comic Sans MSO S\  `&Times New RomanS < :Body Text InO* `"Comic Sans MSO , 8.4 <DL!8  5+ 4 <DL!5XXXS\  `&Times New RomanS  35;CKOU[a11.(a)(1) a.i.1.a.' i. 359=AEIMQ2 o o o) (\ Y`Symbol 359?CGKOS3 1. o o,  35;AGMSY_41.a.i.1.a.i.1.a.. i.#|x(U$..      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CEUS.,3X#XX3XX#XX3X#  _       WW$ XX#       $   CHAPTER4.5:INTERMOLECULARFORCES$ v݌ W Ќ  X-X X#XXX-   KXX##LKWhydoeshydrogenmeltat!259OC,whiletungstenmeltsat T 3380OC?Whyissodiumsoftwhileironishard?Thedifferences B inphysicalpropertiesamongelementsandcompoundsrelateto  thedifferenttypesofbondingandthestrengthofthatbonding #  ineachofthematerials. h   Whenanatomoffluorinebondswithanotheratomoffluorine,a   stablemoleculeofF2results.Thesharingofelectronsfillsthe 7  valenceorbitalsandastableconfigurationisachieved.Ifthe |%  temperatureisloweredsufficiently,fluorinemoleculeswill j  condensetoformaliquid.Ifcoolingiscontinued,theliquidwill   solidifytoformamolecularcrystal.Theenergyislowerinthis K arrangementthanwhenthefluorinemoleculesarefreetomove 9 around. ~ Theforcesthatholdsatomstogetherduringbondingareeither _ covalentorionicbonds.Thesearecalled INTRAMOLECULAR M FORCES. Theforcesthatholdthesestablemoleculestogether  incondensedphasesareverydifferent.Theyarecalled .  INTERMOLECULARFORCES andarefoundas Dipoleforces, s VanDerWaalforcesandHydrogenbonds.  a  RECAP: #0!  t  6"h hhDL!X6Intramolecularforces: forcesexerted within amoleculeor &# polyatomicion. V'$  t  H+ 4 <DL!hhhX!HDuringachemicalchange,intramolecularforcesareovercomeand %+(  chemicalbondsarebroken.Therefore,theseforcesinfluencethe j,*!  chemicalpropertiesofsubstances. -X+"  t  9"h hhDL!X!9 Intermolecularforces: forcesofattractionandrepulsionthat W  act between moleculesorions. E  t  H+ 4 <DL!hhhX!HForcesthatinfluencethephysicalpropertiesofsubstancesare k calledintermolecularforces. Y TheDutchphysicistJohannesvanderWaalextensivelystudied :  intermolecularforces.Tomarkhiscontributionstothe  (  understandingofintermolecularattractions,theseforcesare  m  oftencalledvanderWaalforces.Theyarecategorizedintothe    followinggroups: N   ' (039""  ,E.4 <DL!X!E  _,B%; ; <DL!4X!Bv2  1  .3   ;   dipoledipoleforcesvT݌   Ќ _' X!; ; X!'   ""  ,E.4 <DL!X!E  _,B%; ; <DL!4X!B>2  2  .3   ;   iondipoleforces>݌  Ќ _' X!; ; X!'   ""  ,E.4 <DL!X!E  _,B%; ; <DL!4X!B2  3  .3   ;   induceddipoleforces݌ b  Ќ _' X!; ; X!'   ""  ,E.4 <DL!X!E  _,B%; ; <DL!4X!B2  4  .3   ;   dispersion(London)forces݌ P Ќ _' X!; ; X!'   ""  ,E.4 <DL!X!E  _,B%; ; <DL!4X!B2  5  .3   ;   hydrogenbondingx݌  Ќ _' X!; ; X!'   DipoleDipoleForces:  d  ) (00' / /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LH2 3   4   #L +SInpolarcovalentbondingtheunsymmetricaldistributionof 3 electronicchargesleadtopositiveandnegativechargesin  x themolecules,whicharereferredtoas dipoles. HH݌ " Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L2 3   4   #L +SIntheliquidstate,polarmolecules(dipoles)orient Y#! themselvessothatoppositelychargedendsofthemolecule $G" areneartooneanother.݌ %# Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L2 3   4   #L +STheattractionsbetweentheseoppositechargesarecalled ('$  dipoledipoleforces. ݌ m(& Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L2 3   4   #L +SObservefig.3page258 ݌ )[' Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L!2 3   4   #L +STheseforcesofattractionarelessthanthefullcharges *(  carriedbyionsinioniccrystals.!"݌ <,)! Ќ X$ X!44X!$   IonDipoleForces:  .o,# Ї/ /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L}$2 3   4   #L +SSodiumchlorideandothersolubleionicsolidsdissolvein W polarsolventssuchaswaterbecauseofiondipoleforces.}$}%݌ E Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L&2 3   4   #L +SAn iondipoleforce isforceofattractionbetweenanion  andapolarmolecule(adipole).&'݌ & Ќ X$ X!44X!$   > B+ <DL!X!BEg.NaCldissolvesinwaterbecausetheattractions Y betweenNa+andClionsandthewatermolecules   provideenoughenergytoovercometheforcesthatbind :  theionstogether.  (    m   > InducedIntermolecularForces:      N   , (00) / /""  ,K.4 <DL!  X!K  X,E(4 4 <DL!4X!E+S #L+2 3   4   #L +SInductionofelectricchargeoccurswhenachargeonone <  objectcausesachangeinthedistributionofchargeona   nearbyobject.Eg.Rubbingaballoontoawallisanexample  ofchargingbyinduction.+,݌ b  Ќ X*  X!44X!*   ""  ,K.4 <DL!  X!K  X,E(4 4 <DL!4X!E+S #L.2 3   4   #L +STherearetwotypesofchargedinduceddipoleforces:./݌ P Ќ X*  X!44X!*    H+ 4 <DL!  X!H""  XB+4 44 <DL!X!B  X?% <DL!444X!?@12  1  .3     Ioninduceddipoleforce: resultswhenanioninclose 1 proximitytoanonpolarmoleculedistortstheelectron v densityofthenonpolarmolecule.Themoleculethen d becomesmomentarilypolarized,andthetwospecies  areattractedtoeachother.Eg.Thisforceisactive E duringeverymomentofyourlife,inthebonding 3 betweennonpolarO2moleculesandtheFe2+ionin  x hemoglobin.Ioninduceddipoleforces,therefore,are " partoftheprocessthattransportsvitaloxygen Y#! throughoutyourbody.@12݌ $G" Ќ $ X!  X!$   ""  XB+4 44 <DL!X!B  X?% <DL!444X!?52  2  .3     Dipoleinduceddipoleforce: issimilartothatofan <,)! ioninduceddipoleforce.Inthiscase,however,the -*+" chargeonapolarmoleculeisresponsibleforinducing .o,# thechargeonthenonpolarmolecule.Nonpolargases W suchasoxygenandnitrogendissolve,sparingly,in E waterbecauseofdipoleinduceddipoleforces.56݌  Ќ $ X!  X!$   X-X#L%X-XXX-   %-9  Secret:Thestrengthsoftheattractionswithinmolecules   (intramolecular!thechemicalbonds)determinethechemicalproperties.   Theattractionsbetweenmolecules(intermolecular)determinethe 6  physicalpropertiesofsubstances.%-9j9݌ L! ЌX-XXX-  #LXX-  #LLONDON(DISPERSION)FORCES:#L   E+($  ) (00, / /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L[<2 3   4   #L +SThesharedpairsofelectronsincovalentbondsare -+& constantlyvibrating.[<[=݌ B/,' Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L>2 3   4   #L +SWhilethisappliestoallmolecules,itisofparticular W interestformoleculesthatarenonpolar.>?݌ E Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L@2 3   4   #L +SThebondvibrations(normalconditionofanonpolar  molecule),causemomentary,unevendistributionsofcharge.@A݌ & Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LPC2 3   4   #L +SAnonpolarmoleculebecomesslightlypolarforan instant, k  andcontinuestodothisonarandombutongoingbasis.PCPD݌ Y Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LE2 3   4   #L +SAttheinstantthatonenonpolarmoleculeisinaslightly   polarcondition,itiscapableofinducingadipoleinanearby :  molecule.EF݌  (  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LIH2 3   4   #L +SAnintermolecularforceofattractionresultscalleda  m   dispersionforce. IHII݌    Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LJ2 3   4   #L +SCommonlyreferredtoasLondonforces,inhonourofFritz N  London.JK݌ <  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LL2 3   4   #L +SUnlikeotherintermolecularforces,dispersion(London)   forcesactbetweenanyparticles,polarorotherwise.LM݌  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LO2 3   4   #L +STheyarethemainintermolecularforcesthatactbetween b  nonpolarmolecules.OP݌ P Ќ X$ X!44X!$   " "  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L`Q2 3   4   #L +SObservefigure4page258.`Q`R݌  Ќ X$ X!44X!$   " "  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LYS2 3   4   #L +SLondonForcesareaboutonetenthofforceofmostdipole 1 interactionsandaretheweakestofalltheelectricalforces v thatactbetweenatomsormolecules.YSYT݌ d Ќ X$ X!44X!$   " "  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LU2 3   4   #L +STheseforceshelptoexplainwhynonpolarsubstancessuch  asnoblegasesandthehalogenscondenseintoliquidsand E thenfreezeintosolidswhenthetemperatureislowered 3 sufficiently.UV݌  x Ќ X$ X!44X!$   " "  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LX2 3   4   #L +SIngeneral,theyalsoexplainwhyliquidscomposedof " discretemoleculeswithnopermanentdipoleattractions Y#! havelowboilingpointsrelativetotheirmolecularmasses.XY݌ $G" Ќ X$ X!44X!$   " "  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L[2 3   4   #L +SItisalsotruethatcompoundsinthesolidstatethatare %# boundmainlybythistypeofattractionhaverathersoft ('$ crystals,areeasilydeformed,andvaporizeeasily.[\݌ m(& Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L/^2 3   4   #L +SBecauseofthelowintermolecularforces,themeltingpoints )[' arelowandevaporationtakesplaceeasilythatitmayoccur *(  atroomtemperature.Ex.Solidssuchasiodinecrystals, <,)! naphthalene(mothballs)andparadichlorobenzeneall -*+" evaporateatroomtemperaturequiteeasily./^/_݌ .o,# Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Lra2 3   4   #L +SObserveTable1,page259tocompareboilingpointsof W certainsubstances.rarb݌ E Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Lc2 3   4   #L +SWriteouttheSummary:PredictingwithDipoleDipoleand  LondonForcesonpage259260.cd݌ & Ќ X$ X!44X!$   PracticeProblem:Page260261 :  ЀQuestions#1(a)(f),2(a)(b),3(a)(b),4(b),6  (   #L HYDROGENBONDS:#L   m(& / /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L5g2 3   4   #L +SAdipoledipoleinteractionthatisverysignificantinmany %+(  biologicalmoleculesandsomeinorganicmolecules,suchas j,*!  H2O(l).5g5h݌ -X+" Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Li2 3   4   #L +SHydrogenbondingisaparticularlystrongformofdipole W  dipoleattractionthatexistsbetweenahydrogenatomina E polarbondedmoleculethatcontainsbondssuchasHO,H  N,orHF,andanunsharedpairofelectronsonanother & small,electronegativeatomsuchasO,N,orF.Observe k figure5,page261.ij݌ Y Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #LQm2 3   4   #L +SWhenhydrogenisbondedF,O,N,thestrongforceof   attractionexertedbythesethreeveryelectronegative :  atomsdrawstheelectrondensityfromthehydrogenatom  (  inthepolarbondedmolecule,leavingthehydrogenatom  m  withapartialpositivecharge.QmQn݌    Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L{p2 3   4   #L +SThisdipoleiseasilyattractedtothepartiallynegativelone N  paironanearbyelectronegativeatom:F,OandN.{p{q݌ <  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Lr2 3   4   #L +SAhydrogenbondisonlyabout5%asstrongasasingle   covalentbond.rs݌  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Lu2 3   4   #L +SHowever,insubstancesthatcontainnumeroushydrogen b  bondstheimpactofhydrogenbondingcanbesignificant. P Ex.ThedoublehelixstructureofDNA.uv݌  Ќ X$ X!44X!$   Observethefollowinggraph.Whatdoesthisgraphportray m(& aboutcertainsubstances? )['  Solution: <,)!   -*+" / /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Lx2 3   4   #L +SYoucanseetheeffectofhydrogenbondingclearlyinthe W  boilingpointdata.xy݌ E Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Lz2 3   4   #L +STheincreaseinb.p.frommethane,CH4,totin(IV)hydride,  SnH4,isduetoanincreaseinthenumberofelectrons.z{݌ & Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Lo}2 3   4   #L +STherefore,therearelargerdispersionforces,sincemore k electronsareabletotemporarilyshiftfromonepartofthe Y moleculetoanother.o}o~݌   Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L2 3   4   #L +SInSnH4,thisresultsingreaterintermolecularforcesof :  attraction.݌  (  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L?2 3   4   #L +SThereisnohydrogenbondinginthesesubstances,because  m  therearenolonepairsonthemolecules.??݌    Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L2 3   4   #L +SHowever,thehydrides,onlyshowtheexpectedtrendbased N  ondispersionforcesforthelargermasshydrides.݌ <  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L2 3   4   #L +SThesmallestmasshydrides,NH3,H2O,andHF,have   relativelyhighb.p.,indicatingstrongintermolecularforces  causedbyhydrogenbonding.݌ b  Ќ X$ X!44X!$   &#L#L#L#L ,E.4 <DL!X!E  &  WhyistherenohydrogenbondinginH2SandH2Se,which d haveunsharedpairsontheircentralatoms?&F݌  Ќ ,* X!4X!*#L#L#L#L  / /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L̋2 3   4   #L +SNeitherSnoSeissmallenoughorelectronegativeenough " tosupporthydrogenbonding.̋̌݌ Y#! Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L2 3   4   #L +SThus,H2O(withitssmallandveryelectronegativeOatom) $G" hasamuchhigherb.p.thanSandSe.݌ %# Ќ X$ X!44X!$     -*+" ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L2 3   4   #L +SHydrogenbondingalsoexplainswhysomesubstanceshave W  unexpectedlylowvapourpressure,highheatsof E vaporizationandhighmeltingpoints.݌  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #L22 3   4   #L +SInorderforvaporizationormeltingtotakeplace,molecules & mustbeseparated.22݌ k Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E+S #Lu2 3   4   #L +SEnergymustbeexpendedtobreakhydrogenbondsandthus Y breakdownthelargerclustersofmoleculesintoseparate   molecules.uu݌ :  Ќ X$ X!44X!$   CECE., #L        & Y   OtherPhysicalPropertiesofLiquids kenԌ N  Ќ  #L #L#L CE.,CE.,  X-X#LX#XXX-'YN XX#  / /""  ,E.4 <DL!X!E  ,E(` ` <DL!4X!E#L +S #LG2 3   `   #L +SReadpages262263Gf݌  Ќ ' X!` ` X!'   XB+4 44 <DL!X!BDefinetheterms:   ' (00) ""  XXE+4 44 <DL!444X!E   X<" <DL!444X!<U2(  a  )3      adhesionU;݌ s Ќ X*444X!<X!*   ""  XXE+4 44 <DL!444X!E   X<" <DL!444X!<2(  b  )3      cohesion݌ a Ќ X*444X!<X!*   ""  XXE+4 44 <DL!444X!E   X<" <DL!444X!<2(  c  )3      surfacetension͡݌  Ќ X*444X!<X!*   ""  XXE+4 44 <DL!444X!E   X<" <DL!444X!<2(  d  )3      meniscus݌ B Ќ X*444X!<X!*   ""  XXE+4 44 <DL!444X!E   X<" <DL!444X!<2(  e  )3      volatilitye݌ 0 Ќ X*444X!<X!*   ""  XXE+4 44 <DL!444X!E   X<" <DL!444X!<J2(  f  )3      abilityto wetothersubstancesJ0݌  u Ќ X*444X!<X!*   ""  XXE+4 44 <DL!444X!E   X<" <DL!444X!<12(  g  )3      capillarity1݌ " Ќ X*444X!<X!*   XE+ 4 <DL!444X!E Whataresomeanomaliesofwater? .l,# Ї ) (00' ""  ,E.4 <DL!X!E  ,E(` ` <DL!4X!E+S #L2 3   `   #L +SHydrogenbondingalsoexplainswatersunusualproperty W ofbeinglessdenseinthesolidstatethanintheliquid E state.݌  Ќ ' X!` ` X!'   ""  ,E.4 <DL!X!E  ,E(` ` <DL!4X!E+S #L2 3   `   #L +S Recall: fromtheKMT,lowertemperaturescauseliquid & moleculestomoveslowerthanintheirgaseousstates. k Whenliquidssolidify,theKEoftheparticlesisnolonger Y enoughtopreventtheintermolecularforcesof   attractionfromcausingparticlestosticktogether.For :  mostsubstances,theirsolidstatesaredenserthantheir  (  liquidstates.݌  m  Ќ ' X!` ` X!'   ""  ,E.4 <DL!X!E  ,E(` ` <DL!4X!E+S #LV2 3   `   #L +SWhenwaterfreezes,however,thewatermoleculespack    insuchawaythatthesolidstateis less densethanthe N  liquidstate.VV݌ <  Ќ ' X!` ` X!'   ""  ,E.4 <DL!X!E  ,E(` ` <DL!4X!E+S #L2 3   `   #L +SWatermoleculesaligninaspecificpatternsothat   hydrogenatomsofonemoleculeareorientedtowardthe  oxygenatomofanothermolecule(fig.10,page263).݌ b  Ќ ' X!` ` X!'   ""  ,E.4 <DL!X!E  ,E(` ` <DL!4X!E+S #L2 3   `   #L +SIfwatermoleculesbehavedasmostmoleculesdo,then P lakewaterwouldfreezefromthebottomup,ratherthan  fromthetopdown.݌ 1 Ќ ' X!` ` X!'   ""  ,E.4 <DL!X!E  ,E(` ` <DL!4X!E+S #L2 3   `   #L +STheconsequencesforaquaticlife,andonorganisms(like v us)thatdependonaquaticecosystems,wouldbe d profound.݌  Ќ ' X!` ` X!'   ""  ,E.4 <DL!X!E  ,E(` ` <DL!4X!E+S #L2 3   `   #L +SBecauseicefloatsonwater,itinsulatesthewater E beneathit,preventingitfromfreezing.݌ 3 Ќ ' X!` ` X!'   Explainthesolubilityofcertainsubstancesinwater. $G"   #L#L#L#L      &   @  J#LTHEGOLDENRULE @ľ !<Ԍ -*+" Ќ  #LJ#L#L   '- $/,# !#L#L#L#L     &  !ؿ  J#L LIKEDISSOLVESLIKE!ؿY !<5Ԍ W Ќ  #LJ#L#L  X-X#LX#XXX-'WM"KXX##LK    &  "  PracticeProblems:Page264265" !<Ԍ  ЌX-X#LX#XXX-  KXX##LK'̀Questions:#9(a)(d),11,12 j Read:Summarypage265   Read:CurrentResearchIntermolecularForces ~ '  ЀPage265266  l  Questions:Page266267 M  ̀#1(a)(b)(c),3(a)(c),4(b)(c)(e),5,7,8,11(a)(d)   X-X#LX#XXX- -0-, Ї KXX##LK      &     WORKSHEET:PROPERTIESOFLIQUIDS  ! r<"N N N CDL!  X!<+XXXX-12 3   N   X-XX+XWhydoeswaterformbeadeddropletsonsurfacessuchas   leaves,waxedcarhoods,andwaxedpaper?10݌ # Ќ r- X!N N N CX!- >  ""  ?( <DL!X!?  > r<"N N N CDL!  X!<+XXXX-2 3   N   X-XX+XHowdoesaballpointpenwork?݌ 9 Ќ r- X!N N N CX!- >  ""  ?( <DL!X!?  > r<"N N N CDL!  X!<+XXXX-2 3   N   X-XX+XHowdoesatowelwork?݌ O Ќ r- X!N N N CX!- >  ""  ?( <DL!X!?  > r<"N N N CDL!  X!<+XXXX-2 3   N   X-XX+XWhydoeswaterformaconcavemeniscusinatube,while e mercuryformsaconvexmeniscus?݌ {$ Ќ r- X!N N N CX!- >  ""  ?( <DL!X!?  > r<"N N N CDL!  X!<+XXXX-2 3   N   X-XX+XWhydoesliquidhoneyflowsoslowlyfromaspoon?݌ : Ќ r- X!N N N CX!- >  ""  ?( <DL!X!?  > r<"N N N CDL!  X!<+XXXX-2 3   N   X-XX+XWhydosomemotoristschangetodifferentmotoroils P overthecourseoftheyear?݌  f Ќ r- X!N N N CX!- >  ""  B+` ` ` <DL!X!B   X?"4 44DL!` ` ` X!?I2(  2  )3   4   Basedonyourinferencesandexplanations,developdefinitionsforthe #! followingterms:surfacetension,capillarity,andviscosity.I/݌ %"  Ќ X- X!444X!-   Analysis:  A'$"  . (00' / /X#XXX-""  ,E.4 <DL!X!E  } ,E(  <DL!4X!E2  1  .3      X-XXX#Compareyourinferencesandexplanationswiththosethatyoufound m)'$ inreferencesources.݌ *,(% Ќ ' X! X!' }  X#XXX-""  ,E.4 <DL!X!E  } ,E(  <DL!4X!E2  2  .3      X-XXX#Listthesourcesyouhaveusedtocompareyourexplanations.݌ +B)& Ќ ' X! X!' }  X#XXX-""  ,E.4 <DL!X!E  } ,E(  <DL!4X!EM2  3  .3      X-XXX#Explainwhereyourreasoningmayhaveledyouastray,forthose ,X*' casesinwhichyourideasdidnotmatchcloselywithreference -n+( sourceinformation.M<݌ .,) Ќ ' X! X!' }   /-* X#XXX-