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Reaction Kinetics Multiple Choice
January 1999
1.Consider the reaction:
Ca (s)+ 2H2O (l)Ca(OH)2(aq) + H2(g)
At a certain temperature, 2.50 g Ca reacts completely in 30.0 seconds.
The rate of consumption of Ca is
A. 0.00208 mol/min
. 0.0833 mol/min
C. 0.!25 mol/min". 5.00 mol/min
2.The minimum amount of energy re#uired to o$ercome the energy %arrier in a chemicalreaction is the
A. heat of reaction.. acti$ation energy.
C. &' of the reactants.
". enthalpy of the products.
3.An acti$ated comple( is a chemical species that is
A. sta%le and has lo) *'.
. sta%le and has high *'.
C. unsta%le and has lo) *'.". unsta%le and has high *'.
4.A certain reaction is a%le to proceed %y $arious mechanisms. 'ach mechanism has a
different 'aand results in a different o$erall rate. +hich of the follo)ing %est descri%es
the relationship %et)een the 'a$alues and the rates
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5.Consider the follo)ing *' diagram:
The for)ard reaction can %e descri%ed as
6.Consider the follo)ing reaction mechanism:
-n this reaction, 2 is a
A. product.
. catalyst.
C. reactant.". reaction intermediate.
April 1999
1.The slo)est of the follo)ing reactions is
A. Aga#1 Cla#1AgCl s1
. 3a#1
a#122 l1
C. 3a 2a#1 2*43a#1a3*412s1
". Cus1 2Aga#1Cu
2a#1 2Ags1
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2.The rate of a chemical reaction is e#ual to the slope of a graph )ith the a(es la%eled
3.Consider the follo)ing reaction:
C4 g1 22 g1C2g1 22 g1 heat
The diagram )hich represents the relationship %et)een rate and temperature is:
4.+hich of the follo)ing descri%es the energy of colliding particles as reacting
molecules approach each other
5. The a$erage inetic energy of colliding particles can %e increased %y
A. adding a catalyst.. increasing pressure.
C. increasing temperature.
". increasing reactant concentration.
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6. A su%stance that increases the rate of a chemical reaction and may %e reco$ered
unchanged at the end of the reaction is an1
A. product.
. catalyst.
C. acti$ated comple(.". reaction intermediate.
7. Consider the follo)ing *' diagram for a re$ersi%le reaction:
June 1999
1.+hich of the follo)ing can %e used to represent the rate of a reaction
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2.Consider the follo)ing reaction:
222 l122 l1 2 g1
+hich graph sho)s the relationship %et)een rate of consumption of 22 and time
3. Consider the follo)ing reaction:
6gs1 2Cl a#12g1 6gCl2a#1
The rate of this reaction increases )hen more magnesium is added. This change is caused
%y the
A. addition of a catalyst.
. increase in surface area.
C. change in nature of the reactants.
". increase in concentration of reactants.
4. Consider the follo)ing *' diagram:
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5.+hich graph sho)s the relationship %et)een acti$ation energy 'a)and temperature
6.A catalyst changes the rate of a reaction %y
A. changing .
. increasing the temperature.
C. decreasing the energy of the products.". pro$iding an alternate reaction mechanism.
August 1999
1.At room temperature, )hich of the follo)ing reactions is fastest
A. 2H2(g) + O2 (g)2H2O(g)B. Pb2+(aq) + 2I
-(aq)PbI2(s)
C. 4Fe(s)+ 3O2(g)2Fe2O3(s)
D. Cu(s)+ 2Ag
+
(aq)
Cu
2+
(aq) + 2Ag(s)
2.Consider the follo)ing reaction:
C4g1 22 g1C2 g1 22 g1
At a certain temperature, !.0 mol C4is consumed in 4.0 minutes.The rate of production of 2 is
A. 0.25 mol/min. 0.50 mol/min
C. 2.0 mol/min
". 8.0 mol/min
3.Consider the follo)ing reaction in a closed system:
2g1 -2g1 2HI(g)+hich of the follo)ing )ill cause the rate of the for)ard reaction to decrease
A. 2 is added.
. A catalyst is added.
C. The $olume is increased.
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". The temperature is increased.
4.The changes in *' and &', as reactant molecules approach each other, can %e
represented %y
5.Consider the follo)ing *' diagram:
+hich of the follo)ing descri%es this reaction
6.A chemical reaction that gi$es off energy is
A. e(othermic and is positi$e.
. e(othermic and is negati$e.
C. endothermic and is positi$e.
". endothermic and is negati$e.
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+hich of the follo)ing descri%es the system a%o$e
5.-ncreasing the temperature of a reaction increases the reaction rate %y
-. increasing fre#uency of collisions
--. increasing the inetic energy of collision---. decreasing the potential energy of collision
A. - only.. - and -- only.
C. -- and --- only.
". -, -- and ---.
6.+hat effect does a catalyst ha$e on a reaction
A. -t changes the of a reaction.
. -t increases the inetic energy of the reactants.
C. -t decreases the potential energy of the products.
". -t pro$ides a reaction mechanism )ith a lo)er acti$ation energy.
April 2000
1. At 259C, )hich of the follo)ing reactions is fastest
A. 2g1 -2g12-g1
. Aga#1 -a#1Ag-s1
C. C!2s1 2g1C2g1 2g1
". 5C242
a#1 26n4a#1 !
a#1!C2 g1 26n2a#1 82l1
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2. Consider the graph for the follo)ing reaction:
CaC3s1 2Cl a#1
CaCl2a#1 C2 g1 2l1
The a$erage rate of reaction is greatest in the time inter$al
A. 0 ! minute.. 0 2 minutes.
C. 0 3 minutes.
". 0 4 minutes.
3.+hich of the follo)ing changes )ill increase the a$erage inetic energy of reactant
molecules
A. adding a catalyst. increasing the temperature
C. increasing the surface area
". increasing the concentration
4.Consider the follo)ing potential energy diagram:
+hich of the follo)ing represents the heat of reaction, , for the for)ard reaction
A. -
. --C. ---
". -;
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5. +hen a catalyst is added to a reaction
-. the heat of reaction increases
--. a ne) mechanism is pro$ided---. the e#uili%rium constant increases
A. -- only
. - and -- only
C. -- and --- only". -, -- and ---
6.Consider the follo)ing mechanism for a reaction:/s
--. g/min---. 6/min
A. - only.
. - and -- only.C. -- and --- only.
". -, -- and ---.
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3.Consider the follo)ing reaction:n s1 2Cl a#1nCl2a#1 2g1
A graph of concentration of Cl $s time could %e represented %y
4.Consider the follo)ing e(periments, each in$ol$ing e#ual masses of 7inc and !0.0 m>
of acid:
The rate of reaction in order from fastest to slo)est is
A. - ? -- ? ---. -- ? - ? ---
C. --- ? - ? --
". --- ? -- ? -
5.+hat happens to the energy of reactant molecules as they approach one another
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6.Consider the follo)ing reaction mechanism:
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C. -- and --- only.
". -, -- and ---.
4.+hich of the follo)ing is true for an acti$ated comple(
A. sta%le and has lo) *'. sta%le and has high *'
C. unsta%le and has lo) *'
". unsta%le and has high *'
5. As you increase the temperature of a reaction, the
A. rate increases and the time re#uired for the reaction increases.. rate increases and the time re#uired for the reaction decreases.
C. rate decreases and the time re#uired for the reaction increases.
". rate decreases and the time re#uired for the reaction decreases.
6.+hich of the follo)ing potential energy cur$es represents a cataly7ed endothermic
reaction in the for)ard direction
A. -
. --
C. ---". -;
January 2001
1.+hich of the follo)ing units could %e used to e(press reaction rate
A. m>/s. m>/g
C. g/m>
". m>/mol
2.Consider the reaction:
n s1 2Cl a#1nCl2a#1 2g1
The rate of production of nCl2, can %e increased %y
A. decreasing the ClD.
. increasing the temperature.C. increasing the $olume of 2.
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". decreasing the surface area of n .
3.The statement,the minimum energy needed to achieve a successful collision,defines
A. entropy.. acti$ation energy.
C. the " of reaction.
". the acti$ated comple(.
4.As an acti$ated comple( changes to products,
A. potential energy changes to inetic energy.. inetic energy changes to potential energy.
C. inetic energy changes to acti$ation energy.
". potential energy changes to acti$ation energy.
5.Consider the follo)ing *' diagram for an uncatalysed and a cataly7ed reaction:
+hich of the follo)ing descri%es the for)ard cataly7ed reaction
6.A su%stance that increases the rate of a reaction )ithout appearing in the e#uation
for the o$erall reaction is an1
A. product.
. catalyst.
C. reactant.
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". intermediate.
April 2001
1.+hich of the follo)ing reactions occurs most rapidly at standard conditions
A. 2Be s1 2g12Bes1
. Cas1 3Cs1CaC2s1 Cg1
C.
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5.+hat is the relationship %et)een the acti$ation energy and the rate of a reaction
A. +hen the acti$ation energy is high, the rate of reaction is fast.. +hen the acti$ation energy is lo), the rate of reaction is slo).
C. +hen the acti$ation energy is high, the rate of reaction is slo).
". There is no relationship %et)een acti$ation energy and rate of reaction.
6.Consider the follo)ing reaction mechanism:
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4.+hich of the follo)ing reactions is endothermic
A. C4g1 22g1C2g1 22l1 8F0.3G
. 2=a22 s1 22 l128H.0 G4=aa#1 2g1
C. Cas1 2l1Ca12a#1 I 5.2G
". Cas1 3Cs1CaC2s1 Cg1 I 44.8G
5. The follo)ing diagram sho)s reactant molecules approaching one another:
+hat is happening to the inetic energy and the potential energy
6.A proposed mechanism for a reaction is:
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A. !.5 @ !03mol/s
. 3.0 @ !03mol/s
C. .0 @!03mol/s". !.5 @!02mol/s
2.Consider the follo)ing reaction:
3Be23s1 Cg1
2Be34s1 C2g1 4G+hich of the follo)ing )ould cause the rate of the reaction to increase
A. remo$ing the Be34. decreasing the temperature
C. increasing the surface area of Be23". increasing the $olume of the reaction $essel
3.Activation energy is descri%ed as
A. the energy of the acti$ated comple(.. a point on the *' diagram )here &' I *'.
C. the unsta%le high *' structural arrangement of atoms.". the minimum *' difference %et)een the acti$ated comple( and the reactants.
4. +hat happens to the acti$ation energy and )hen a catalyst is added to a reaction
5.Consider the follo)ing potential energy diagram for a reaction:
+hat is the $alue of for this reaction
A. !20 G
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. 30 G
C. 30 G
". !20 G
6.A su%stance that is produced in one step in a reaction mechanism and consumed
in a su%se#uent step, )ithout appearing in the o$erall reaction, is an1
A. catalyst.
. product.C. reactant.
". intermediate.
January 2002
1.+hich of the follo)ing has the greatest reaction rate
A. Cs1 2g1C2g1
. 222 l122 l1 2 g1
C. 2Al s1 3CuCl2a#12AlCl3a#1 3Cus1
". =aCla#1 Ag=3a#1AgCls1 =a=3a#1
2. +hich factor e(plains )hy potassium generally reacts faster than sodium
A. surface area
. temperature
C. concentration". nature of reactants
3.+hat happens to the *' and &' of the reactants particles as the acti$ated comple( isformed
*' &' .A. increases decreases
. increases increases
C. decreases decreases
". decreases increases
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4. Consider the follo)ing *' diagram:
+hat are the $alues of and acti$ation energy 'a1 for the for)ard reaction
5.Consider the follo)ing reaction mechanism:
+hich of the follo)ing is a reactant in the o$erall reaction
A. Cl. Cl
C. CCl3
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". CCl3
6.Consider the follo)ing *' diagram for a cataly7ed and uncataly7ed reaction:
+hich of the follo)ing descri%es the reverse reaction
April 2002
1.+hich of the follo)ing could %e used to descri%e the rate of a reaction
A. change in time
change in mass
. change in mass
change in $olume
C. change in $olume
change in time
". change in $olume
change in mass
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2.Consider the follo)ing reaction:
222a#122l1 2g1
+hich factor e(plains )hy the a%o$e reaction speeds up in the presence of 6n2s1
A. temperature C. nature of reactants
. concentration ". presence of catalyst
3.+hat happens to the potential energy and the total energy as an acti$ated comple(
changes into products
4.Consider the follo)ing *' diagram:
+hich of the follo)ing descri%es the type of reaction and for the reverse reaction
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5.Consider the follo)ing diagram for a cataly7ed and uncataly7ed reaction:
+hich of the follo)ing descri%es the forward reaction
6.Consider the follo)ing reaction mechanism:
=2
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June 2002
1. +hich of the follo)ing has the lo)est rate of reaction
A. *%s1 CuCl2a#1 K Cus1 *%Cl2a#1 . Cla#1 =aa#1K 2l1 =aCla#1 C. 2
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C. 400 &G
". 500 &G
5. Consider the follo)ing reaction mechanism:
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2. +hich factor e(plains )hy coal dust is e(plosi$e
A. temperature . surface area
C. concentration
". addition of catalyst
3. As an acti$ated comple( changes into products, )hat changes occur in the chemical%onds of the acti$ated comple( and the *' of the system
onds *'
A. form increases. form decreases
C. %rea increases
". %rea decreases
4. Consider the follo)ing *' diagram:
+hich of the follo)ing descri%es M and the type of reaction in the for)ard direction
MG1
Type ofLeaction
A. 50 e(othermic
. 50 endothermicC. 50 e(othermic
". 50 endothermic
5. Consider the follo)ing *' diagram for a cataly7ed and uncataly7ed reaction:
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+hich of the follo)ing descri%es the for)ard reaction
Leaction Acti$ation'nergy G1
MG1
A. cataly7ed 300 !00. uncataly7ed 300 !00
C. cataly7ed 400 !00
". uncataly7ed 400 !00
6. Consider the follo)ing reaction mechanism:
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2. Consider the follo)ing reaction:
Be23s1 2Als1K Al23s1 2Bel1
-f 0.50 mol of Be is produced in !0.0sec, )hat is the rate of consumption
of Be23in mol/s
A. 5.0 O !02 mol/s
. 2.5 O !02 mol/s C. !.0 O !0! mol/s
". 5.0 mol/s
3. +hich of the follo)ing )ould result in a successful collision %et)een
reactant particles
A. particles ha$e sufficient &'
. particles con$ert all their *' into &'
C. particles are in an e(cited state and are cataly7ed ". particles ha$e sufficient &' and proper molecular orientation
4. +hich of the follo)ing %est descri%es the 'aof a fast reaction and the sta%ility of
its acti$ated comple(
'a Acti$ated
Comple(
A. small unsta%le
. small sta%le
C. large unsta%le
". large sta%le
5. o) does the addition of a catalyst increase the reaction rate of an endothermicreaction
A. -t reduces the M of the reaction. . -t increases the M of the reaction.
C. -t reduces the re#uired acti$ation energy.
". -t causes the reaction to %ecome e(othermic.
6. Consider the follo)ing *' diagram:
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+hat is the acti$ation energy for the reversereaction
A. 0 G
. 20 G
C. 40 G ". 0 G
April 2003
1. Consider the follo)ing reaction occurring in an open container:
CaC3s1 2Cla#1 K CaCl2a#1 2l1 C2g1
The reaction rate could %e calculated %y using )hich of the follo)ing
A. a change in ClD
. a decrease in p $alue C. a change in gas pressure
". a decrease in the mass of the system
2. +hich of the follo)ing does notaffect %oth homogeneous and heterogeneous
reaction rates
A. addition of a catalyst
. change in temperature
C. change in surface area ". change in concentration
3. o) do &' and *' change as reactant particles collide )ith each other
&' *'
A. increases increases
. increases decreases
C. decreases increases
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". decreases decreases
4. Pnder )hich of the follo)ing conditions )ill the reaction rate decrease for a
reaction )hich goes to completion
A. A catalyst is remo$ed. . *roducts are remo$ed.
C. Temperature is increased. ".
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2. Consider the follo)ing reaction:
2=g1 2g1K 2=2g1 M I !!4 G
o) could the rate of this reaction %e increased
A. Leduce the pressure.
. -ncrease the $olume.
C. Lemo$e some =2g1.". -ncrease the temperature.
3. An acti$ated comple( can %e descri%ed as
A. a particle of ma(imum &' and minimum *'.
. a sta%le particle found in a reaction mechanism.
C. an unsta%le particle that is neither reactant nor product.
". a particle )hich is first used then regenerated in a reaction mechanism.
4. +hich of the follo)ing could result in an increase in reaction rate
A. an increase in the acti$ation energy
. an increase in the reaction enthalpy
C. an increase in the fre#uency of collisions ". an increase in the potential energy of the acti$ated comple(
5. Consider the follo)ing *' diagram:
+hich of the follo)ing descri%es the energy $alue indicated %y -
A. heat of reaction . acti$ation energy for the re$erse reaction
C. acti$ation energy for the for)ard reaction
". potential energy of the reaction intermediate
6. Consider the follo)ing reaction mechanism and o$erall reaction:
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+hat is the catalyst in this mechanism
A. g1 . =g1 C. =2g1 ". sunlight
August 2003
1. +hich of the follo)ing reactions )ould %e slo)est at room temperature
A. ns1
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". the acti$ation energy is con$erted to inetic energy
4. Consider the follo)ing information for a re$ersi%le chemical reaction:
! for)ard acti$ation energy I 20 G
2 re$erse acti$ation energy I 30 G
+hich of the follo)ing descri%es the reaction type and enthalpy change for the for)ard reaction
Leaction Type M ;alue
A. e(othermic !0 G
. e(othermic !0 G
C. endothermic !0 G
". endothermic !0 G
5. Consider the follo)ing e(perimental results:
'(periment ! '(periment 2
Leactants Be2a#1 6n4a#1 6n4
a#1 2C24a#1
Temperature 20 40
Concentration 0.5 6 solutions !.0 6 solutions
Lates Bast
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January 2004
1. +hich of the follo)ing factors only affects the rate of heterogeneous reactions
A. nature of reactants . presence of a catalyst
C. temperature of reactants
". surface area of reactants
2. Consider the follo)ing reactions in open systems:
-. 22g1 2g1 K 22g1
--. CaC3g1K Cas1 C2g1
---. Cas1
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Leaction *' of Acti$atedComple( G1
MG1
A. cataly7ed !00 50
. uncataly7ed 300 50
C. cataly7ed 250 50". uncataly7ed !50 50
5. Consider the follo)ing reaction:
2=g1 2g1 K 2=2g1
+hy )ould this reaction pro%a%ly in$ol$e more than one step
A. There is insufficient acti$ation energy.
. This reaction has high acti$ation energy.
C. Leactions %et)een gases are typically slo). ". A successful collision %et)een more than t)o molecules is unliely.
6. Consider the follo)ing reaction mechanism:
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Unit I Multiple Choice Answers
anuar! 1""" #pril 1""" une 1""" #ugust 1"""
! C ! $ ! $ ! %
2 % 2 $ 2 # 2 %
3 $ 3 $ 3 % 3 C4 C 4 # 4 C 4 #
5 # 5 C 5 # 5 $
C % $ %
anuar! 2&&& #pril 2&&& une 2&&& #ugust 2&&&
! % ! % ! # ! C
2 C 2 # 2 $ 2 %
3 $ 3 % 3 C 3 C
4 # 4 $ 4 C 4 $
5 % 5 # 5 % 5 %
$ $ % $
anuar! 2&&1 #pril 2&&1 une 2&&1 #ugust 2&&1
! # ! $ ! % ! #
2 % 2 # 2 % 2 C
3 % 3 C 3 $ 3 $
4 # 4 % 4 $ 4 C
5 # 5 C 5 % 5 %
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% $ C $
anuar! 2&&2 #pril 2&&2 une 2&&2 #ugust 2&&2
! $ ! C ! # ! C
2 $ 2 $ 2 C 2 %
3 # 3 $ 3 C 3 $4 # 4 % 4 % 4 $
5 $ 5 # 5 % 5 $
# $ C #
anuar! 2&&3 #pril 2&&3 une 2&&3 #ugust 2&&3
! C ! $ ! C ! #
2 % 2 C 2 $ 2 $
3 $ 3 C 3 C 3 C
4 # 4 # 4 C 4 #
5 C 5 # 5 % 5 C
$ C % C
anuar! 2&&4
! $
2 %
3 $
4 %
5 $
$