Download Chem fundamentals 1a

Announcements,10/6/16
Turn-inassignment1isnowavailable(see“Assignments:
https://canvas.uw.edu/courses/1065255/assignments/3358655 )
Itisdue10/13andwillbediscussed/presentedinclasson
thatday.
Videofrom10/5isnowpostedonPanopto pageandalso
under“Modules>session2”
The12principles
• OriginatedwiththetextbookGreenChemistry
TheoryandPractice,byPaulAnastas andJohn
Warner,1998.
• Somearefocusedonspecificaspectsofchemical
practice,othersaremoregeneral
• Threescalesofapplication:individualchemicals;
chemicalproducts,andchemicalprocesses
• Thesegroupintothreemainareas:minimizing
waste,reducingtoxicity,andenhancing
sustainability inchemicalprocessesandproducts.
Session3
GreenChemistryprinciplesoverview
Chemistrybasics:reactions,equations,efficiency
GCPrinciples1-6
minimizing waste
reducingtoxicity/hazard
enhancing sustainability
1. Prevention: Itisbettertoprevent wastethantotreatorcleanupwasteafterit
hasbeencreated. 2. AtomEconomy:Syntheticmethods shouldbedesigned tomaximizethe
incorporation ofallmaterials used intheprocess intothefinalproduct.
3. LessHazardous Chemical Syntheses:Wherever practicable, syntheticmethods
shouldbedesigned touseandgenerate substances thatpossess littleorno
toxicitytohumanhealthandtheenvironment.
4. DesigningSafer Chemicals:Chemicalproducts shouldbedesigned toaffect their
desired function whileminimizingtheir toxicity.
5. Safer Solvents andAuxiliaries: The useofauxiliarysubstances (e.g., solvents,
separation agents, etc.)shouldbemadeunnecessary wherever possible and
innocuous whenused.
6. DesignforEnergyEfficiency: Energyrequirements ofchemicalprocesses should
berecognized fortheir environmental andeconomicimpactsandshouldbe
minimized.Ifpossible, syntheticmethods shouldbeconductedatambient
temperature andpressure.
GCPrinciples7-12
minimizing waste
reducingtoxicity/hazard
enhancing sustainability
7. UseofRenewable Feedstocks: Arawmaterialorfeedstockshouldberenewablerather
thandepleting whenevertechnically andeconomically practicable.
8. ReduceDerivatives:Unnecessary derivatization (useofblockinggroups,protection/
deprotection, temporarymodification ofphysical/chemical processes) shouldbe
minimized oravoidedifpossible, because suchstepsrequireadditional reagentsandcan
generatewaste.
9. Catalysis: Catalyticreagents (asselective aspossible) aresuperiortostoichiometric
reagents.
10. DesignforDegradation:Chemical productsshouldbedesigned sothatattheendoftheir
functiontheybreakdownintoinnocuous degradationproductsanddonotpersist inthe
environment.
11. Real-time analysis forPollutionPrevention:Analyticalmethodologies needtobefurther
developed toallowforreal-time,in-process monitoringandcontrolpriortothe
formationofhazardoussubstances.
12. InherentlySaferChemistryforAccidentPrevention:Substancesandtheformofa
substance usedinachemical processshouldbechosentominimizethepotential for
chemical accidents, includingreleases, explosions, andfires.
GreenEngineeringPrinciples
1. InherentRatherThanCircumstantial:Designersneedtostrivetoensurethatallmaterialsand
energyinputsandoutputsareasinherentlynonhazardousaspossible.
2. PreventionInsteadofTreatment:Itisbettertopreventwastethantotreatorcleanupwaste
afteritisformed.
3. DesignforSeparation:Separationandpurificationoperationsshouldbedesignedtominimize
energyconsumptionandmaterialsuse.
4. MaximizeEfficiency:Products,processes,andsystemsshouldbedesignedtomaximizemass,
energy,space,andtimeefficiency.
5. Output-PulledVersusInput-Pushed:Products,processes,andsystemsshouldbe"output
pulled"ratherthan"inputpushed"throughtheuseofenergyandmaterials.
6. ConserveComplexity:Embeddedentropyandcomplexitymustbeviewedasaninvestment
whenmakingdesignchoicesonrecycle,reuse,orbeneficialdisposition.
7. DurabilityRatherThanImmortality:Targeteddurability,notimmortality,shouldbeadesign
goal.
8. MeetNeed,MinimizeExcess:Designforunnecessarycapacityorcapability(e.g., "onesizefits
all")solutionsshouldbeconsideredadesignflaw.
9. MinimizeMaterialDiversity:Materialdiversityinmulticomponentproductsshouldbe
minimizedtopromotedisassemblyandvalueretention.
10. IntegrateMaterialandEnergyFlows:Designofproducts,processes,andsystemsmustinclude
integrationandinterconnectivitywithavailableenergyandmaterialsflows.
11. DesignforCommercial"Afterlife:Products,processes,andsystemsshouldbedesignedfor
performanceinacommercial"afterlife.”
12. RenewableRatherThanDepleting:Materialandenergyinputsshouldberenewable rather
thandepleting.
GreenEngineeringPrinciple#1
InherentRatherThanCircumstantial
• “Designers need tostrivetoensure thatallmaterials andenergy
inputsandoutputsareasinherently nonhazardous aspossible.”
• Inherentlysafe(r):anunloadedorinoperablegun.Circumstantially
safe:aloadedgunwiththesafetyon.
• Whenwerelyonmanagingachemicalriskbymanagingthe
opportunityforexposuresthroughcontainmentofthehazard,thatis
circumstantiallysafe.Whenwemanagetheriskbyeliminatingthe
hazard(byreplacingitwithanon-toxicchemical),thatisinherently
safe.
• Requires asystemsperspective; i.e.,theability todomassand
energy balancesaroundaunitoperation,achemical process,a
facility,oranevenlarger,morecomprehensive andcomplex
systemlike anindustrial parkorpetrochemical complex.
• Greenengineering demands—even injustthisfirstprinciple—
thatyoupayattentiontoalargersetofspecifications ordesign
constraintsthanyouotherwise might.
Discussion:principles
Prepassignment:
• (1)Picktwoofthe(12)GreenChemistryprinciplesandread
themoredetailedexplanationprovidedbytheACSweb
pages(listedunder"Module0"). Considerandbeprepared
todiscusshowtheprinciplesyouselectedmightmatter:(a)
toachemist;(b)toaformulationschemist;(c)toan
environmentalprotectionscientist;(d)toapublichealth
official.
• (2)Reflectingonthediscussionofsustainabilityandthinking
abouttheGCandGEprinciplesastoolstoreachsustainable
societiesglobally,whatwouldbeyourwishlistfortheideal
chemicalpesticide? Whatwouldbeitspropertiesandwhat
wouldyouspecifyabouthowitismade,used,anddisposed
of?
• Relatedquestion: Whatisthedistinctionbetweencalling
something“green”andcallingit“greener”?
Writingbalanced chemicalreactionequations
Comments onchemical notation:
Singlelines=single bonds=2electrons
Doublelines=doublebonds=4electrons
Nonbondingelectrons (depends ontheelement) arenotshown
butarecountedtobalance electrons.Ohas4nonbonding
electrons; Nhas2.
Organicchemical structuresoftenarewrittentoomittheH
atoms,whichareassumed (togiveeachCatotalof4bonds).C
atomsarejustindicated asabendinastructure’sline.Inthis
notation,maleic anhydridewouldlooklike: Session3B:
Chem fundamentals1:
atoms
molecules
reactions
Writingbalanced chemicalreactionequations: massbalance
Missing 6H andhaveoneextraO
(webalance Hbyadding
waterasareactionproduct)
w(C4H8)+x(O2)
y(C4H2O3)+z(H2O)
w(C4H8)+x(O2)
y(C4H2O3)+z(H2O)(assume wandy=1)
1(C4H8)+x(O2)
1(C4H2O3)+3(H2O)(tobalance H,z=3)
1(C4H8)+3(O2)
1(C4H2O3)+3(H2O)(tobalance O,x=3)
Writingbalanced chemicalreactionequations: massandelectronbalance
Using balancedchemical reactionequations
3
+H–O–H
+3(H2O)
+H–O–H
1(C4H8)+3(O2)
1(C4H2O3)+3(H2O)
Valence electrons: 24
3636
24
60valenceelectrons inreactants=60valenceelectrons inproducts
1.
2.
3.
4.
Chargebalance: nochargesinreactantsorproducts!
1(C4H8)+3(O2)
1.
2.
3.
4.
1(C4H2O3)+3(H2O)
1(C4H8)+3(O2)
Atomicweights:
C=12g/mol
H=1g/mol
O=16g/mol
Howmanymolesin10gof1-butene?
Howmanygramsofmaleic anhydridewouldthismake?
Howmanymolesofoxygenwouldthisrequireataminimum?
Ifyoustartwith10gof1butene,andmake10gofmaleic anhydride,
whatisyourpercentyield?
MWs:
1(C4H2O3)+3(H2O)
48+2+48=982+16=18
Q1:10gof2-butene=10/56=0.18moles
Q2:0.18moles2-butene=0.18molesmaleic anhydride=0.18*98=17.6g
Q3:0.18moles requiresatleast 3x0.18moles O2 =0.54moles O2
Q4:Q2calculated thetheoretical (100%)yield:17.6g.Theactualyieldwas
10g;10/17.6=56.8%
Atomicweights:
C=12g/mol
H=1g/mol
O=16g/mol
Howmanymolesin10gof1-butene?
Howmanygramsofmaleic anhydridewouldthismake?
Howmanymolesofoxygenwouldthisrequireataminimum?
Ifyoustartwith10gof1butene,andmake10gofmaleic anhydride,
whatisyourpercentyield?
Examples
For1gofaceticacid,howmanygramsofNaOHisneeded toneutralizeit?
Acetic Acid
1(C4H8)+3(O2)
48+8=5616+16=32
1(C4H2O3)+3(H2O)
NaOH
Mass(g)
1g
?????
MW (gmol-1)
60.02
40.00
Mole(mol)
0.01665mol
Mass(g)ofNaOHneeded:
!"#$% = ()**+,-./0-.(2)
(,-./0-)45.6278(2+,- 9: )
0.01665mol
0.01665mol x 40gmol-1
=0.67g
0.67gofNaOHisthe
minimum amountyou
needtocomplete the
reaction
WhatisLimitingReagentandYield
• Theamountofreagentthatdictatestheamountof
productofinterestswillform
Acetic Acid
NaOH
Sodium Acetate
Mass(g)
1g
1g
-
-
MW (gmol-1)
60.02
40.00
82.034
18.02
Mole(mol)
0.0167mol
0.025
TheLimiting Reagent?____Acetic Acid_____
!"#$% = 0.0167mol
Theoretical Yield: 82.034x0.0167
=1.37 g
Water
0.0167mol
Theoretical Yield:
18.02x0.0167
=0.30 g
()**+,-./0-.(2)
(,-./0-)45.6278(2+,- 9:)
Q:Attheendofreaction, theactualyieldofsodiumacetatewasonly0.5g.Whatisthepercent yield?
LimitingReagentProblem
2Li+2H2Oà
2LiOH+H2
Ifweadd6molesofwaterand2molesofLi,whichisthe
limitingreagent? Li
HowmanymolesofLiOH doyouexpect?OfH2?
LiOH:2moles
H2:1mole
HowmanygramsofH2 wouldbeformedbythecomplete
reactionof80.57gofLiwithwater?
??23.21gH2???
??11.70gH2???
??5.804gH2 ???
Updated(2/1/16):theansweris11.60becausemolecular
weightofH2 ,twohydrogenatoms,is2.016gmol-1
PercentYield:
0.5/1.37x100%=
36.5%
(endofslidestobeusedinclass)
Slidestohelpyoureview
UsetheseslidestogetherwiththeKahnacademyfilm
clipstogooverfundamentalsofatoms,molecules,
andreactionequations.
Chemistryfundamentals1:
atoms,molecules,bonds
• ReadCh 4inBCEtext
• Whatyoushouldknow:
• Atoms:periodic tableinfo,periodic trends, valence electrons and
charge;atomicweights, molesandAvogadro’snumber
• Chemicalbondingandtheoctetrule
• Simpleorganiccompoundtypesandnames
• Statesofmatter (gas,liquid,solid)
• Ionicandneutral molecules
• Mixtures; acidsandbases
• Skillsyoushouldhave:
• Calculatemolecular weights frommolecular formulas
• Determine ifamolecular formulareflects stablecombiningratiosof
elements
• Balance simplechemicalreaction equations formass,charge, and
electrons
KahnAcademytitlesforthistopic
• Atoms,compounds,andions
• Stoichiometryandmolecularcomposition
• Chemicalreactions
• Electronicstructureofatoms
• Periodictable
• Chemicalbonds
• Statesofmatterandintermolecularforces
Hierarchyofmatter
• Mixtures(heterogeneous)
example:dirt
• Mixtures(homogeneous)
example:puresaltwater;brass
• (pure)Chemicalsubstances:
madeofonekindofmolecule.
example:salt,NaCl
• Elements:madeofonekindof
atom.Example:elementaliron,
Fe0.
• (subatomicparticles:electrons,
neutrons,protons)
• (subnuclear particles)
Theatom
THEPERIODICTABLE
ElementalProperties
• Eachelement represents 1typeofatom,defined bythenumber
ofprotons(andelectronsforaneutralform)
• Theperiodic tablepresents thesearrangedbyincreasing numbers
ofprotonsandelectrons
• Columns represent GROUPSofelements sharingoutermost
(valence) electron numbersandthereforechemical behaviors
• Rowsintheperiodic tabledepictincreasingsize andnumber of
subshell electrons/protons, andconfersome trendsinbehavior
fromlowtohigh
• Periodicproperties letyoupredictsome behaviors fromthe
position ofanelement intheperiodicchart:
• Atomicsize(radius)
• Numberandconfigurationofvalenceelectrons
• Commonoxidationstates,combiningratiosandtendencytoform
covalentbonds!!
• Ionizationenergy
• Electronegativity
• Meltingandboilingpoints
• Volatility
• Acidity
ThePeriodicTable
Main
Elements
Noble
Gases
TheAtom&ElectronShells
TheBohrModel
Highestenergyshellisthe
outerone.
Atomstrytoretaintheir
lowestenergystate.
Thus– electronsareputin
shellsfromtheinsideout.
1n– 2e- (“s”orbital=2e–)
2n– 8e- (“s”+“p”orbitals)
3n– 18e- (“s”+“p”+“d”orb.)
2610
Transition
Elements
ImageadaptedfromKhanAcademy
TheOctetRule:especiallyfor
maingroup(1,2,13-18)elements
OutermostShell=Valence
Shell
Valenceshell#electrons
determinesreactivity.Why?
TheOctetRule:Atomsare
stablewhenthevalence
shellcontains8electrons,or
whenitisfull.
Carbon0 has4valenceelectrons
Carbon+4 has8valenceelectrons
AtomicTheory&ThePeriodic
Table:
Trend4:Electronegativity
ElectronAffinityis
theenergychange
thatoccurswhenan
electronisgainedby
anatom.
Electronegativity =
tendencyofanatom
toattractelectrons
(thatelectronisn’t
necessarily
transferred).
FromAtomstoMolecules:
Ifanelementhashighelectronegativity,whatdoes
thatmean?
- Howwillitbehavetowardsotheratoms?Electron
richones?
- Whatkindofcompoundsdoesitform?
- Howdoesitbehavewithinamolecule?
CASESTUDYDISCUSSION
• Whatiswrongwithbrominatedandchlorinated
molecules?
http://www.rsc.org/periodic-table/
• Whatcontainsthem?
• Howcouldyoureplacethem?
• WhatwasApple’sstrategy?
TopicsCovered
Molecules
DifferentModels
AtomicStructures
• CommonTerminologies
• OrganicMolecules
• Nomenclature
• pKa,aciddissociationconstant
• Boilingpointandmeltingpoint
• ChemBioDraw Tutorial
AtomicWeight
Electronic Structures
• Theatomicweightofanelementistheweightof6.022X
1023 atomsofit
• AtomicWeightunit:gmol-1
• Theatomicweightsoftheelementsareincludedinthe
periodictableoftheelements.
• General/OrganicChemistry
• Transferofe• Valancee- counting
• Computation Chemistry
• Predictreactivity(in-silico approach)
• Hybridization(fusingoftwoorbitals)
AtomicNumber
(#ofprotons)
AtomicWeight
(theweight(g)whenthere
are6.022x1023 Natoms)
WhatareMolecules
MolecularWeight
• Moleculesarecollectionofatoms(≥2)thatare
tightlyboundtogether
• Amoleculeisthesmallestamountofapure
substancethatcanexist
H2 O
• Themolecularweightofamoleculeistheweightof6.022
x1023 suchmolecules.Themolecularweightofamolecule
isequaltothesumoftheatomicweightofitsconstituting
atoms.
C6H12O6
NaOH
H2
N2
He
NaCl
AgNO3
MolecularWeightofTableSalt
Whichone,a)orb),calculatestheMW ofNaCl?
a)Mw (NaCl)=22.990+35.453=58.443gmol-1
b)Mw (NaCl)=11+17=28gmol-1
Because it’scalculated withatomicnumberwhich
doesn’taccountforthemassofneutrons
MolecularWeightofGlucose
Glucosemolecularformula:C6H12O6
=180.1559gmol-1
Whatistheweight(g)of6molesofglucose?
=180.1559x6
=1,080.93g
Avogadro’sNumber
• Avogadro’snumber=6.022x1023
• #ofATOMorMOLECULEper1moleofANYsubstrate
• 1moleofglucose=6.022x1023 glucosemolecule
• 1moleofwater=6.022x1023water molecule
• 1moleofhelium=6.022x1023heliumatom
Moles
• CommonmetricsinChemistry
• 1gofC=5.01x1022 Catoms
• 1gofSi=2.15x1022 Siatoms
• Itisunitless,likedozen
• Molewasusedtoaccountforthedifferencein
atomic/molecularweightofdifferentelement
• !"#$% = ThePeriodicTable
()**,;)8,+,4+,-./0-.(2)
<8,+6/,4+,-./0-)45.6278(2+,- 9: )
BasicOrganicChemistryRules
• Undernormal/neutralcircumstances…
Element
Bondsformation
Hydrogen(H)
1
Halogen(Cl),(Br)or (I)
1
Oxygen(O)
2(with2lonepairs)
Nitrogen (N)
3(with1lonepair)
Carbon(C)
4
Phosphorus(P)
3(with1lonepair)or5
OrganicNomenclature
• Namingorganiccompounds
• Commonname
• Easiertocommunicate
• Triethyl amine andMethamphetamine
• IUPACname
• Basedonstructure,canreconstructstructurebasedonthename
• N,N-diethylethanamine andN-methyl-1-phenylpropan-2-amine
• Memorize
Hydrocarbons
• Therearefourbasictypesoforganichydrocarbons,thosechemicals
withonlycarbonandhydrogen:
•
•
•
•
1.Singlebonds(alkane):suffixis"ane",formulaCnH(2n+2)
2.Doublebonds(alkene):suffixis"ene",formulaCnH2n
3.Triplebonds(alkyne):suffixis"yne",formulaCnH(2n-2)
4.(Mono)Cycliccompounds:useprefix"cyclo“,formula????
• Prefixandsuffix
• Functionalgroups
• Basicrules
Prefixes
• Numberofcarbons
•
•
•
•
•
•
•
•
•
•
1
2
3
4
5
6
7
8
9
10
methethpropbutpenthexheptoctnondec-
• "C6H14"--- alkane,6carbons,"hexane”
• "C6H12"--- alkeneorcycloalkane,6carbons,"hexene”or
“Cyclohexane”
MoreExamples
FunctionalGroups
SomeFunctionalGroupsKey
Characteristic
FunctionalGroup
FunctionalGroupscanaffectofamolecule:
a) Melting andboilingpoints
b) Reactivity
c) Toxicity
d) Solubility
*Typical
Characteristic
Examples
Amine
R–NH2
Basic, bittertaste,
feelslippery
Trimethylamine
Sulfide
R–S–R
Rotten Smell
Dimethylsufide
Methanethiol
Ester
R-C(O)-OR
SweetSmell
Isoamyl acetate
Ethyl acetate
Cyanide
R–CN
“bitteralmond”
ormaybeodorless
Stayaway
CarboxylicAcid
R-C(O)-OR
Sour
AceticAcid
Benzoic acid
*Mostlyapplicable tosmall molecules