Chemistry12

LeChatelier’sPrincipleWorksheetName:Date:Block:

1. StateLeChatelier'sPrinciple.Giveanexampleinyouranswer.2. Inordertodecidewhateffectachangeintotalpressurewillhaveonanequilibriumsystem

withgases,whatisthefirstthingyoushoulddowhengiventhebalancedequation?3. Predictwhichwaythefollowingequilibriumsystemswillshiftwhenthetotalpressureis

increased.(NOTE:Somemayhavenoshift) a)N2(g)+O2(g)⇋2NO(g) b)2SO2(g)+O2(g)⇋2SO3(g) c)4NH3(g)+5O2(g)⇋4NO(g)+6H2O(g)4. Whichwaywillthefollowingequilibriumshiftifthetotalpressureonthesystemis

decreased?Explainyouranswer.2C2H6(g)+7O2(g)⇋4CO2(g)+6H2O(g)

Forthequestions5,6,and7,usethefollowingequation:

N2O4(g)+heat⇋2NO2(g) colourless darkbrown 5. ExplainwhyaflaskfilledwithNO2(g)andN2O4(g)willgetdarkerwhenheated. 6. ExplainwhyasyringecontainingNO2gaswillfirstgetdarkerandthenlighterincolourwhen

compressed.

7. ExplainwhyaflaskcontainingNO2willgetlighterincolourwhenputintoicewater.

A system equilibriumwill shift to alleviatean imposedstress

Addupthe of molesofgas of each side of the equation

heshift 2gasmot on eachside

rightleft

dPmeans 9V shifttosidew moregasmolecules shift right

healingwill cause a shift right No would increase anddarkbrowncolourwoulddeepen

Compressionis 9P so the r n would shift lefttoward side w less gasmolecules

de heat Shiflett colour lightens

8. Hydrogenperoxidedecomposesasfollows: H2O2(l)⇋H2(g)+O2(g) ΔH=+187kJ Predictthedirectionofequilibriumshift(leftorright)byeachofthefollowingimposed

changes: a) Increasethe[H2] b) Decreasethe[O2] c) Decreasethetotalpressure d) Increasethetemperature e) AddMnO2asacatalyst f) Sketchagraphoftherelativeconcentrationsofeachspeciesastheprocessoutlinedina-e

ofthisquestioniscarriedout.9. Forthereaction:

2NO(g)+Cl2(g)⇋2NOCl(g)ΔH=-77kJ

statetheoptimalpressureandtemperatureconditionsnecessaryformaximumproductionofNOCl.

(highorlow?)_______________pressureand(highorlow?)_______________temperature10. Forthereaction:

3H2(g)+N2(g)⇋2NH3(g)+heat statetheoptimalconditionsforahighyieldofammonia(NH3). (highorlow?)_______________pressureand(highorlow?)_______________temperature

leftright

µ rightrightno shift

H2O is liquid concentration remains constant

CHI h

Oil Tr

l l I i la b c d e

high low

high low

11. Considerthefollowingequilibriumandstatewhichway(leftorright)theequilibriumshiftswheneachofthechangesbelowaremade,thensketchagraphoftherelativeconcentrations.

heat+CH4(g)+2H2S(g)⇋CS2(g)+4H2(g) a) CH4gasisadded b) CS2gasisremoved c) H2gasisadded d) Thetotalvolumeofthecontainerisdecreased e) Thetemperatureisincreased f) Thetotalpressureisdecreased12. Usingthefollowingequilibrium,statewhatwouldhappentotheequilibriumconcentrationof

CH3OHgaswheneachofthefollowingchangesaremade: CO(g)+2H2(g)⇋CH3OH(g)ΔH=-75.2kJ

a) COgasisaddedtothecontainer b) Thetemperatureisincreased c) Thetotalpressureofthesystemisincreased d) H2gasisremovedfromthesystem e) Acatalystisadded f) Thetotalvolumeofthecontainerisincreased

rightrightleft

AP left

rightright

city I

CHA 4ccs.IT

TCHzIN

I l I I lk b c d e f

increase shiftrightdecrease shift left

increase shift rightdecrease shift left

no change no shiftdecrease shift left

13. Giventhefollowingequilibriumsystem,statewhichwaytheequilibriumwillshiftwhenthechangesbelowaremade,thensketchagraphoftherelativeconcentrations.

2C2H6(g)+7O2(g)⇋4CO2(g)+6H2O(g)+heat a) Thevolumeofthecontainerishalved b) Thetemperatureisdecreased c) CO2isaddedtothecontainer d) Thetotalpressureisincreased e) O2gasisremovedfromthesystem f) Neongasisaddedtoincreasethetotalpressure h) Acatalystisadded

leftrightleftleftleft

no shift left

i

14. GiventhefollowinggraphshowingtheconcentrationsofspeciesA,BandC,fillinthetable

below.Theequilibriumequationis: A(g)+B(g)⇋C(g)ΔH=-65kJ

TimeI TimeII TimeIII TimeIV[A]Decreaseorincrease?

[B]Decreaseorincrease?

[C]Decreaseorincrease?

Shift?

Imposedstress?

decrease increase increase decreasespike thendecrease increase increase decrease

spike thenincrease decrease decrease increaseright left left rightadd B add heat add C removeheat