1. 2....The Haber-Bosch Process 2. Keq The Haber-Bosch Process Almost all of the world’s ammonia...
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Chemistry 12 Equilibrium III Name: Date: Block: 1. The Haber-Bosch Process 2. Keq The Haber-Bosch Process Almost all of the world’s ammonia is produced via the Haber-Bosch process and almost all of our inorganic nitrogen compounds are produced from this ammonia. More than 100 million tonnes of ammonia with a value in excess of $600 million are produced annually. About 80% of the world’s ammonia is used to produce fertilizers. Other products include explosives, plastics, fibres and dyes. German chemist Fritz Haber developed the equipment and procedures from producing ammonia (NH3) from its constituent elements (N2 and H2) in 1910. In 1918, he received the Nobel Prize in chemistry for his accomplishment. In 1931, another German chemist, Carl Bosch, won the Nobel Prize in chemistry, in part for transforming the process to an industrial scale. The balanced equation and enthalpy for the reaction are: N2(g) +3H2 (g) ⇋ 2 NH3 (g) ΔH= -92 kJ/mol The Equilibrium Constant Consider the following equation: N2(g) +3H2 (g) ⇋ 2 NH3 (g) At equilibrium, the forward and reverse rates are equal. Forward rate: Reverse rate: Rearranging to isolate the constants, we get: In this case, k f k r provides a constant that chemists call the equilibrium constant, Keq. Keq = dependent on C s dependent on of reactants CIs of products edm kfCNz CHIP KrcNHz 2 Iss o in general Cprodects ratio w reactants knits
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
