1. 2....The Haber-Bosch Process 2. Keq The Haber-Bosch Process Almost all of the world’s ammonia...
Transcript of 1. 2....The Haber-Bosch Process 2. Keq The Haber-Bosch Process Almost all of the world’s ammonia...
Chemistry12EquilibriumIII
Name:Date:Block:
1. TheHaber-BoschProcess2. Keq
TheHaber-BoschProcessAlmostalloftheworld’sammoniaisproducedviatheHaber-Boschprocessandalmostallofourinorganicnitrogencompoundsareproducedfromthisammonia.Morethan100milliontonnesofammoniawithavalueinexcessof$600millionareproducedannually.About80%oftheworld’sammoniaisusedtoproducefertilizers.Otherproductsincludeexplosives,plastics,fibresanddyes.GermanchemistFritzHaberdevelopedtheequipmentandproceduresfromproducingammonia(NH3)fromitsconstituentelements(N2andH2)in1910.In1918,hereceivedtheNobelPrizeinchemistryforhisaccomplishment.In1931,anotherGermanchemist,CarlBosch,wontheNobelPrizeinchemistry,inpartfortransformingtheprocesstoanindustrialscale.Thebalancedequationandenthalpyforthereactionare: N2(g)+3H2(g)⇋2NH3(g) ΔH=-92kJ/molTheEquilibriumConstantConsiderthefollowingequation:
N2(g)+3H2(g)⇋2NH3(g)
Atequilibrium,theforwardandreverseratesareequal.Forwardrate:
Reverserate:
Rearrangingtoisolatetheconstants,weget:
Inthiscase,kfkrprovidesaconstantthatchemistscalltheequilibriumconstant,Keq.
Keq=
dependent on C s dependent onof reactants CIs of products
edm kfCNz CHIP KrcNHz2
Isso
ingeneral Cprodects ratio w
reactants knits
Regardlessoftheinitialconcentrationsofreactantsandproducts,whenequilibriumisachievedandtheequilibriumconcentrationsaresubstitutedintothisexpression,thecalculatedvaluewillalwaysbethesame.
Theequilibriumlawstatesthatforthegeneralbalancedequation:wA+xB⇋yC+zD
wherew,x,yandzarecoefficientstobalancetheequation.
Balanceandwritetheequilibriumexpressionforthefollowingreactions:___C2H2(g)+___H2(g)⇋___CH4(g)
___SO2(g)+___O2(g)⇋___SO3(g)
___HCl(g)+___O2(g)⇋___Cl2(g)+___H2O(g)
___CH4(g)+___H2O(g)⇋___CO(g)+___H2(g)
1.Thefollowinggasesareatequilibriuminaflaskat423oC:4.56x10-3MH2,7.4x10-4MI2,and1.35x10-2MHI.Whatistheequilibriumconstantforthereactionatthistemperature?
___H2(g)+___I2(g)⇋___HI(g)2.Aquantityof3.88x10-3MNO2isatequilibriumwith1.73x10-4MN2O4at60oC.Whatistheequilibriumconstantforthereaction?
___NO2(g)⇋___N2O4(g)
I
keqecproducti f.CMZ
reactants Aw BTX
I 3 2 2 l Z
keg CHy keg GOICHICHIS GOD cos
4 2 2 3
keg Ector keg CdtHCl 4 027 GHyCHIT
2
keg CHDIata fIEIE I.E
2
Keg NOPEi HI
ChemicalsinliquidsorsolidstatesareNOTincludedintheequilibriumexpressions!!
• Liquidsandsolidshaveafixeddensityandtherefore,afixedconcentration.• Theonlyexceptioniswhentwoliquidsappearinthesameequation,thuseachliquid
dilutestheother.Balanceandwritetheequilibriumexpressionforthefollowingreactions:___Cr2O7-2(aq)+___H2O(l)⇋___H+(aq)+_____CrO42-(aq)
___NaCl(s)⇋___Na+(aq)+___Cl-(aq)
___H2(g)+___Br2(l)⇋___HBr(g)
___B2H6(g)+___O2(g)⇋___B2O3(s)+___H2O(g)
HebdenWorkbook:Pg.60#31,34,35:
2 or more liquids
2 2 XKeq CROFT CH'T Keq Nat 7
to T2 3 X 3
keg CHBI keq CHOPCHI
BzHDfq3
RelativeSizeofKeqRecallthat…
Keq=[products][reactants]
Keq>1 Keq= _________________arefavoured.
Keq<1 Keq= _________________arefavoured.
Whichofthefollowingisleastlikelytofavourtheformationofproducts?
A. 2H2O(g)⇋2H2(g)+O2(g) Keq=7.3x10-18B. N2O(g)+NO2(g)⇋3NO(g) Keq=4.2x10-4C. N2O4(g)⇋2NO2(g) Keq=4.5D. SO2(g)+NO2(g)⇋NO(g)+SO3(g) Keq=85
Explainyouranswertothequestionabove:DoesthevalueofKeqchangewhen…Concentrationchanges?
N2(g)+3H2(g)⇋2NH3(g) ΔH=-92kJ/mol
• Whathappenstotherelativeconcentrationsofeachspecieswhen…o NH3isincreased?
N2(g)+3H2(g)⇋2NH3(g) Keq=
Overall,theconcentration___________staysthesame,soKeq___________________________.
o H2isdecreased?N2(g)+3H2(g)⇋2NH3(g) Keq=
Overall,theconcentration___________staysthesame,soKeq___________________________.
largerafffrtoducts
PRODUCTS
edm
TeamProducts
Cproducts ReactantsREACTANTS Wyarger
amountof
reactants0 aim
BK keg is smallest in a reactantswere favoured the most
q F fd Products TReactants T
ratio staythe same
9 fr f Cproducts dw Creactants d
netdecreaseratio stays the same
changes in C T have theeffect on keg value
Temperaturechanges?
N2(g)+3H2(g)⇋2NH3(g) ΔH=-92kJ/mol
• Whathappenstotherelativeconcentrationsofeachspecieswhen…o Heatisincreased?
N2(g)+3H2(g)⇋2NH3(g)+heat Keq=
Concentrationofreactants__________________.Concentrationofproducts__________________.Therefore,Keqwill__________________.
o Heatisdecreased?N2(g)+3H2(g)⇋2NH3(g)+heat Keq=
Concentrationofreactants__________________.Concentrationofproducts__________________.Therefore,Keqwill__________________.
Forthefollowingequations,statewhethertheKeqwouldincreaseordecrease:Equation: Temperature
change:Keqresult:
G+H⇋J ΔH=-92kJ/mol Increase
A+B+heat⇋ C Increase
P+Q⇋ R+S+150kJ Decrease
W+X+100kJ⇋Y+Z Decrease
N+M⇋P ΔH=+125kJ/mol Increase
r F d r EET Epjdincreasesdecreases
decrease
d d r d ffjf 9decreasesincreases
increasetemperature is the only factor
that has an effect on keg value
keg CPIheat
CRIW
r rd r
d drheat
Forthefollowingequations,determinewhetherthereactionisendothermicorexothermicfromtheobservations:Equation: Temperature
Change:Keq: ExoorEndo:
A+B⇋C+D Increase Increases
E+F⇋ G+H Decrease Decrease
I+J⇋ K+L Increase Decrease
M+N⇋O+P Decrease Increase
Q+R⇋S+T Increase Decrease
Forthefollowingequations,determinewhetherthetemperaturehasincreasedordecreased:Equation: Keqresult: Temperature
change:
G+H⇋J ΔH=-92kJ/mol Increased
A+B+heat⇋ C Decreased
P+Q+150kJ⇋ R+S Increased
W+X+100kJ⇋Y+Z Decreased
N+M⇋P ΔH=+125kJ/mol Increased
endoendoexo
exo
exo
in
PracticeQuestions:1. Balanceandwritetheequilibriumexpressionforeachofthefollowing:
a. _____Fe(s)+_____H+(aq)⇋_____H2(g)+_____Fe2+(aq)
b. _____I-(aq)+_____Cl2(aq)⇋_____I2(s)+_____Cl-(aq)
c. _____CaO(s)+_____CO2(g)⇋_____CaCO3(s)
d. _____CO2(g)⇋_____CO2(aq)
e. _____Na2O(s)⇋_____Na(l)+_____O2(g)
2. A2.0Lflaskcontains0.38molCH4(g),0.59molC2H2(g),and1.4molH2(g)atequilibrium.
Calculatetheequilibriumconstantforthereaction:2CH4(g)⇋C2H2(g)+3H2(g)
X 2keg CE CHz
2 X 2 CH t
keg CFI1 72412X
16 foilkeg CC0
cod
keg Coz
city 0.382 0 0.19M
GHz 0.59 1 0.30M2 OL
CHz t4me O
7oMkeqCHi3f 7 0 Yo 3d I2I
3. Acylindercontains0.12MCoBr2,0.060MCO,and0.080MBr2atequilibrium.Thevolumeofthecylinderissuddenlydoubled.
COBr2(g)⇋CO(g)+Br2(g)a) Whatisthemolarconcentrationofeachgasimmediatelyafterthevolumeofthe
cylinderisdoubled?
b) Explain,intermsofLeChatelier’sprinciple,whythesystemshiftsrighttorestoreequilibrium.
4. Aclosedflaskcontains0.65mol/LN2and0.85mol/LH2atequilibrium.Whatisthe[NH3]?
N2(g)+3H2(g)⇋2NH3(g) Keq=0.017
HebdenWorkbook:Pg.62#36-46
XXconcentration halved
CoBrz 0.060Mco 0.030M
Brd 0.040M
shift right towardside w moreORIGEQ'M to 0040gas molecules
Vol change 0.030 0.040 O020
keg CNHs
Nz Hz3
Solving for NHS
Nlt keg.CNzt.CHi
NHzJ CO0l7 C0.65C0.85T O 082MT