Chemistry12ReactionKineticsI

Name:Date:Block:

1. CalculatingRates2. MeasuringRates3. FactorsAffectingRates

MonitoringandCalculatingReactionRatesReactionRate=Timeunits: RateUnits:Giventhefollowingequationanddata:

2HNO3(aq)+Cu(s)→NO2(g)+H2O(l)+CuNO3(aq)

Massofcopper(g)

3.26 2.93 2.60

Time(min) 5.00 7.00 9.00

a) Doesthereactionabovehaveaconstantrate?Explainwhyorwhynot.

b) Calculatetherateinunitsof(gCu/min).

c) Calculatetherateinunitsof(moleCu/min).

d) CalculatetherateinmolesHNO3consumedperminute(rememberthemoleratio).

e) Calculatetherateinunitsof(g/min)forHNO3.

changeimeasurabequanh.lychangein time

seconds min gls Llmin etchours

mass of CuW 0.33g

Rate Smog 2.60g3.26gst.me9comin 5comin 497 017gCumin

0 lt uxlmolCu 2.7x103molCuminmin 63.5g

2.7 103 014 x 2n N0z 5.4 103 MolHNozyminmin ImdCu

5.4 103motHNOz 63.0 O34gHN031miamin lmotHN03

Considerthefollowinggraph:

1. IsAareactantoraproduct?Explainyouranswer.

2. Determinethereactionrateat40.secondsand100.seconds.

3. Explainthetrendobservedintermsofreactionkinetics.

product time 0 CA7 0Mas rain progresses A is produced

40 s 100 s

0.61 10.07 477 10.0107740s

rxn slowingdownnot constant ratereactant isbeingusedupandlessproductisbeing produced

MeasuringReactionRatesChangingratesofreactionscanbefoundbymeasuringachangeinoneofthefollowingproperties:

1. Colour

2. Temperature

3. Pressure

4. MassStatefivedifferentmethodsformeasuringtherateofthereactionofanironnailinconcentratedhydrochloricacid:

a. Whatisthebalancedchemicalequation?(HCliscolourless;FeCl2isyellow-orange)

b. Whatpropertieswould/couldyoumonitor?

Δ[HCl]time

ΔpHtime

ΔVolH2time

ΔPH2time

ΔmassH2time

Titrate pHmeter Eudimeter Manometer Balance

M/s pHunits/s mL/s kPa/s g/s

CompleteReactionRatesWorksheet

scolourintensity 5 Amls timeA time

SC s k 6SMStime DtimeSatin AkPa 7 SpitAtime D time

slime

Fees t 2Hchaq Feckcag t H2cgcolourless yellow orange

1 colourintensity yelloworange 5 pH 9morebasic2 Vol Hey 9 6 pressure Hug 93 mass Fees L 7 CHU d4 temp

FactorsAffectingReactionRates

“Whenthe…increases,thentherate….”Reactionratesareaffectedbythefollowingfactors:

1. Temperature• Whenthetemperatureisincreased,theparticleshave_____________________energy.• Willresultinmorefrequentandmoreforcefulcollisions.• Thetimeforthereactiontotakeplacewill__________________thereforethereactionratewill

________________.2. Concentration

• Asthereactantconcentrationincreases,therearemoreparticlestocollidewitheachother.• Thereactionratewill______________________.

3. Pressure• Anincreaseinpressurecausestheparticlestobe_______________together.• Pressureisinverselyproportionalto___________________________.

o Anincreaseinpressureresultsina____________________ofvolumeandviceversa.

4. SurfaceArea/Phase• Withagreaterthesurfaceareaexposed,thereisanincreaseinlocationswherethereaction

cantakeplace• Ex:

• Allowsfor______________________inreactionrate.

increased

decreaseincrease

increaseo T CT o o can 9 C T of

o o j aqueous solutionso o o and gasesvolume gas closer

volumedecrease

o O

lesso o LconcentIV TP Ndp

o oO o

solid Tmore Concentrated

increase

5. Natureofthereactants

• Factorssuchasionizationenergy,electronegativity,ionicandmolecularpolarity,size,complexityofstructure,etc.

• Ingeneral,atroomtemperaturetherateofaqueous>gas>liquid>solid.6. Presenceofacatalyst

• Substancesthatincreasetheratesofchemicalreactionswithoutbeingusedup.• (Aninhibitorisaspeciesthatreducestherateofachemicalreactionbycombiningwitha

reactanttostopitfromreactinginitsusualway.)

Thefollowingreactionistakingplaceataveryslowrateinaclosedcontaineratroomtemperature:

S(s)+O2(g)àSO2(g)Statewhateffecteachofthefollowingprocedureswillhaveontherateofthisreaction,andexplainwhytheprocedurehasthestatedeffect.

a) Thetemperatureisdecreased.

b) MoreO2(g)isaddedinthesamevolume.

c) Thesulphurisgroundupintoapowder.

d) Thevolumeofthecontainerisincreased.

BecarefulwhendiscussingMEASURINGreactionratesandAFFECTINGreactionrates.Reaction1:A(s)+B(aq)àC(aq)+D(g)

• Listtwowaysthereactionratecouldbemeasured:

• Listtwowaysthereactionrateabovecouldbeincreased:Reaction2:E(aq)+F(aq)àG(aq)+H(s)

• Listtwowaysthereactionratecouldbemeasured:

• Listtwowaysthereactionrateabovecouldbedecreased:

rain rate dparticlesslowdown lesschance of asuccessfulcollisionrim rate rmore Ozmolecules available for successfulrxn rate Tincreased location where r n can take

placerxn rate dlower frequency of successful collisions

vol Dg T pressureDog 9mass Acs dlook reactantsTSA Acs catalyst

Hemp r CB

mass H S fVol ofsystem d formation of

precipitated tempinhibitord CET and DCF