Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
2/10/2017 10:51 AM
Copyright © 2017 Dan Dill [email protected]
Lecture 10 CH102 A1 (MWF 9:05 am)
TP CO2 gasat1atm,0oC
isheatedto1atm,60oC;
thencompressedto75atm,60oC;
thencooledto75atm,0oC;
thenexpandedto70atm,0oC.
Atthispoint,theCO2 willbea…
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Friday, February 10, 2017
• Complete:Phasediagrams
Beginch12:Solutionsandtheirbehavior
• Enthalpychangeofsolution:IonicSolutes
gas
supercriticalfluid
liquid
solid
Next:Continuech12:ΔlattH ,ΔaqH and ΔsolnH . Predictingrelativevalues
ofΔlattH andΔaqH
TriplepointYouTubevideo:http://goo.gl/4K1SR
CriticalpointYouTubevideo:http://goo.gl/xo2jU
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Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Copyright © 2017 Dan Dill [email protected]
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Supercritical fluid
Changes of phase
SupercriticaltransitionofliquidCl2 …http://goo.gl/xo2jU
CO2 gasat1atm,0oC
isheatedto1atm,60oC;
thencompressedto75atm,60oC;
thencooledto75atm,0oC;
thenexpandedto70atm,0oC.
Atthispoint,theCO2 willbea…
6
Copyright © 2017 Dan Dill [email protected]
Copyright © 2017 Dan Dill [email protected]
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Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
2/10/2017 10:51 AM
Copyright © 2017 Dan Dill [email protected]
TP CO2 gasat1atm,0oC
isheatedto1atm,60oC;
thencompressedto75atm,60oC;
thencooledto75atm,0oC;
thenexpandedto70atm,0oC.
Atthispoint,theCO2 willbea…
25%
25%
25%
25%
1.
2.
3.
4.
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
gas
supercriticalfluid
liquid
solid
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25%
25%
25%
1.
2.
3.
4.
once
twice
threetimes
noneoftheabove
Response
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Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Copyright © 2017 Dan Dill [email protected]
Phase diagrams are specific to each substance
Water
CO2
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
10
9
Copyright © 2017 Dan Dill [email protected]
H2O phase diagram
IsdensityofliquidH2OgreaterthanthatofsolidH2O?
Howcanwetell?
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Copyright © 2017 Dan Dill [email protected]
Copyright © 2017 Dan Dill [email protected]
Groupquiz CO2 at1atm,0oC
isheatedto1atm,60oC;
thencompressedto75atm,60oC;
thencooledto75atm,0oC;
thenexpandedto70atm,0oC.
Atthispoint,theCO2 willundergone
aphasetransition…
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Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
2/10/2017 10:51 AM
Copyright © 2017 Dan Dill [email protected]
Continue ch 12
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Copyright © 2017 Dan Dill [email protected]
How ionic substances dissolve
NaCl s ⟶Na aq Cl aq
SolutionsandTheirBehavior
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Copyright © 2017 Dan Dill [email protected]
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Copyright © 2017 Dan Dill [email protected]
Ionicsolidsdissolvebytheirionsbeingsurroundedbywater.
<
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+
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+
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+
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+
-
<
Thecollectionofhydratedionsissometimesrepresentedas“salt aq ”.
Forexample,Na aq Cl‒ aq isabbreviatedasNaCl aq
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However,chemically,salt aq doesnotexist.
Itisonlyanabbreviationforthehydratedions,e.g.,Na aq Cl‒ aq
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+
<
<
+
<
Forexample,NaCl s →Na aq Cl‒ aq
<
Recall from CH101: About “NaCl(aq)”, etc.
<
TP Dowegetthesameamountofenergybackfrommakingbonds betweenan
ionandwatermolecules,asittooktobreaktheionicbonds holdinganioninthe
solid?
<
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
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+
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+
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Theenergyisthesame
Moreenergytobreakionbondsinsolid
Moreenergyfrommakingion‐waterbonds
Wedon’tknow
Sincesalt aq doesnotexist,inthiscoursepleasedonotuseit!
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Copyright © 2017 Dan Dill [email protected]
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Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
2/10/2017 10:51 AM
Copyright © 2017 Dan Dill [email protected]
Enthalpy change of solution
Whenanionicsoliddissolvesinwater,dependingontheionicsolid…
thesolutiongetswarmor…
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33%
thesolutiongetscold.
Let’sdevelopaframework withwhichtoanalyzesuchresults.
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Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Lecture 10 CH102 A1 (MWF 9:05 am) Spring 2017
Copyright © 2017 Dan Dill [email protected]
TP Latticeenthalpy,ΔlattH ,istheenthalpychangerequiredtoseparateamoleof
ionicsolidintoitsindividualionsinthegasphase,sothattheyaresofarapart
theynolongerinteractwithoneanotherelectrically.Latticeenthalpy…
1. isalwayspositive
2. isalwaysnegative
3. canbepositiveornegative,dependingontheionicsolid
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Copyright © 2017 Dan Dill [email protected]
Lattice enthalpy, ΔlattH
Writethechemicalequationwhoseenthalpychangeisthelatticeenthalpyof
KCl,ΔlattH.Besuretoincludethestatesofall.
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Copyright © 2017 Dan Dill [email protected]
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