14 Chemical Kinetics

8/9/2019 14 Chemical Kinetics

1/6

1. What is the efect o catalyst on rate constant? [1]

2. How is activation energy afected on adding a catalyst? [1]

3. What do you mean by the term collision re!uency? [2]

". How does collision theory e#$lain ormation o $roducts in a chemical

reaction? [1]

%. What is the drawbac& o collision theory? [2]

'. How does the number o collisions change on increasing the tem$erature? [2]

(. )here is no bar on the no. o collisions among the reaching s$ecies. Why most

o the reactions do not ta&e $lace under normal conditions? [2]

*. +rom the ,g. -1 [2]

-a /alculate 0 or the reaction activation energy or orward reaction.

-b dentiy the curve or catalysed reaction.

-c what is the energy o activation in the $resence o catalyst?

4. )he activation energy o reaction is (%.2 567mol in the absence o a catalyst

and %8.1" 5679ol in the $resence o a catalyst. How many times will the reaction

grow in the $resence o a catalyst i the reaction $roceeds at 2%8/? [2]

18. )he rate o a $articular reaction !uadru$les when the tem$erature changes

rom 243 5 to 313 5. /alculate activation energy or such a reaction. [2]

1. :ive an e#am$le o $seudo ; ,rst order reaction ? [1]

2. Write the e#$ression or hal ; lie $eriod o a ,rst order reaction? [1]

3. < ,rst order reaction is ound to have a rate constant 5 = %.% > 181" sec 1.

+ind hal lie o reaction? [1]

". )he time re!uired to decom$ose @2/l2 to hal o its initial amount is '8 min.

the decom$osition is a ,rst order reaction calculate the rate constant o the

reaction? [2]

%. )he rate constant or the ,rst order decom$osition o A2@% at 2%8/ is 3B182

min1. t the initial concentration o A2@% is 2B183 mol7C How long will it ta&e

to dro$ the concentration to %B18" mol 7C ? [2]

'. Write


2/6

tem$erature range24%5 to 38%5 what would be the activation energy or this

reaction? -E=*.31"6&1 mol1 [3]

4. )he rate constant or a reaction is 1.%> 18( s1 at %88/ and ".%> 18( s1at

1888/. /alculate the value o activation energy or the reaction E=*.31" 651

mol1? [3]

18. Flot a gra$h showing variation o $otential energy with reaction .coordinate?

[1]

1. < catalyst increases the rate constant value.

2. < catalyst lowers the activation energy by ollowing a diferent $ath or the

reaction.

3. )he no. o collisions $er second $er unit volume o the reaction mi#ture is&nown as collision re!uency. t is denoted by G.

".


3/6

'. )he reaction 2A2@% -g K2A@2 -g J@2 -g was studied and the ollowing data

were collected M s.no [A2@%] mol C1 Eate o disa$$earance o [A2@%]-mol7C7min

1. 1.13>182 3">18% 2. 8.*" >182 2%>18% 3. 8.'2>182 1*>18%

Netermine i )he order ii )he rate law. iii Eate constant or the reaction. [3]

(. )he ollowing e#$erimental data was collected or the reactionM /l2 -g J 2A@

-g K 2 A@/l-g )rial ntial conc. @ /l2 -mol7C [A@] mol7C nitial Eate-mol7C7s

1 8.18 8.818 1.2 B 18"

2 8.18 8.838 18.* B 18"

3 8.28 8.838 21.' B 18" /onstruct the rate e!uation or the reaction. [3]

*. Nraw a gra$h or a /oncentration o reactant against time or a Dero order

reaction. b Cog [Eo]7 [E] against time or a ,rst order reaction. [2]

4. What is the use o integrated rate e!uation? [2]

18. +or ,rst order reaction ; < KL Write -1 Niferential rate law. -2 ntegrated

rate law.

1. Hydrolysis o ethyl acetate when concentration o water is very large is an

e#am$le o $seudo ,rst order reaction.

/H3/@@ /2H% J H2@ K /H3 /@@H J /2H%@H.

2. +or a ,rst order reaction the hal lie $eriod is )172 = 8.'43&

'. 18" s1 [1]

2. /onsider the e!uation 2 A@ -! J 2H2 -g K A2 -g J 2H2@ -g )he rate law

or this e!uation is ,rst order with res$ect to H2 and second order with res$ect

to A@. write the rate law or this reaction. [1]

3. )he rate Caw or the reaction 18% 2. 8.*" >182 2%>18% 3. 8.'2>182 1*>18% Neterminei )he order ii )he rate law. iii Eate constant or the reaction. [3]


4/6

(. )he ollowing e#$erimental data was collected or the reactionM /l2 -g J 2A@

-g K 2 A@/l-g )rial ntial conc. @ /l2 -mol7C [A@] mol7C nitial Eate-mol7C7s

1 8.18 8.818 1.2 B 18"

2 8.18 8.838 18.* B 18"

3 8.28 8.838 21.' B 18"

/onstruct the rate e!uation or the reaction. [3]

*. Nraw a gra$h or a /oncentration o reactant against time or a Dero order

reaction. b Cog [Eo]7 [E] against time or a ,rst order reaction. [2]

4. What is the use o integrated rate e!uation? [2]

18. +or ,rst order reaction ; < KL Write -1 Niferential rate law. -2 ntegrated

rate law. [2]

1. a ince the units o rate constant are Cmol1 s1 )he reactions is o second

order. b ince the units o rate constant are s1 )he reaction is o ,rst order.

)he rate o reaction increases eight times.

(. @rder o A@ is 2 Eate law = 5 [/l2] [A@]2

4. Ose o integrated rate e!uation

1. )he value o rate constant can be &nown when concentration o reactant at

diferent times are &nown

2. @rder o a reaction can be determined by the &nowledge o reaction

concentration atdiferent times.

1. s rate o reaction always constant? [1]

2. nlist the actors afecting rate o a reaction? [1]

3. What do you understand by rate law e#$ression? [2]

". s it $ossible to determine or $redict the rate law theoretically by merely

loo&ing at the e!uation? [1]

%. Ne,ne the terms ; i @rder o a reaction [2] ii 9olecularity o a reaction.

'. What are elementary and com$le# reactions? [2]

(. Niferentiate between order and molecularity o a reaction? [2]

*. Netermine the overall order o a reaction which has the rate law [2] E = 5

[


5/6

18. +or the reaction


6/6

%. What is instantaneous rate o a reaction? How is it determined? [2]

'. +or the ollowing reactions write the rate o reaction e#$ression in terms o

reactants and $roducts? [2]

i "AH3 -g J %@2 -g K "A@ -g J 'H2@ -g ii 2A2@% K 2A@2 J @2

(. +or the chemical decom$osition o @2/l2 its initial concentration is 8.*"28

mol7C and ,nal concentration is 8.21% molC1 in 2 hours. What is the average

rate o this reaction? [2]

*. n the e#$ression o rate o reaction in terms o reactants what is the

signi,cance o negative sign? [2]

18. < chemical reaction 2< Q "LJ/ in gas $hase occurs in a closed vessel. )he

concentration o L is ound to be increased by % B 183 mole C1 in 18 second.

/alculate -i the rate o a$$earance o L -ii the rate o disa$$earance o

Documents

14 Chemical Kinetics