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Thermochemistry and Chemical Kinetics
Multiple Choice
Identify the choice that best completes the statement or answers the question
...
Which of the following statements regarding spontaneous changes is false?
a
...
Spontaneity is favored when the dispersal
state without any outside influence
...

b
...
All exothermic reactions are spontaneous
...

_B___ 2
...
a process that is always spontaneous
b
...
release of thermal energy
d
...
Evaluate S0 for the reaction below at 25C and 1 atm
...
91
S (J/molK)
a
...
2 J/K
b
...
4 J/K

2HNO3(aq)
146

+ NO(g)
210
...
287
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+1
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The heat of vaporization of methanol, CH3OH, is 35
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Its boiling point is 64
...
What is the
change in entropy for the vaporization of methanol?
a
...
17
...
17
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104 J/molK
C____ 5
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2NaCl
c
...
2C6H6
d
...
A process occurs spontaneously and Ssystem < 0
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Ssurroundings > 0
d
...

b
...
All of these answers are correct
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The pressure is constant
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Which of the following statements about free energy is false?
a
...
S must be positive for a process to be
processes
...

b
...
S is positive for many spontaneous
processes
...

_C___ 8
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2C2H2(g)
+ 5O2(g)
209
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1409 kJ
b
...
4

+ 2H2O
237
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2470 kJ
d
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Which one of the following statements is not correct?
a
...
When G for a reaction is negative, the
reaction is never spontaneous
...

b
...
When G for a reaction is positive, the
the reaction is not expected to be
reaction is nonspontaneous
...

_D___ 10
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H = +10 kJ, S = 5 J/K
c
...
no such values exist
d
...
The following reaction has G = 0 at 9900C
...
8 kJ  HCN(g) + NH3(g)
a
...
1 J/molK
b
...
1 J/molK

c
...
5 J/molK
d
...
1 J/molK

_C___ 12
...

CH4(g)
+ 2Cl2(g)
0
74
...
75
(kJ/mol)
a
...
360 J/K



CCl4
135
...
27

+ 2H2(g)
0
0

c
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487 J/K

_A___ 13
...


c
...


d
...
In the following reaction,
time?

= 0
...
What is the value of the rate of the reaction at this

A + 3B  AB3

a
...
89 mol/Ls
b
...
67 mol/Ls

c
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22 mol/Ls
d
...
30 mol/Ls

_A___ 15
...
The overall order of the reaction
a
...

c
...

b
...

d
...

_D___ 16
...
What
are the units of k, the specific rate constant, if reaction rate is expressed in units of moles per liter per
second?
a
...
Ms1
b
...
M2s1
_B___ 17
...
If the concentration of A is tripled and the concentration of B is doubled, the
reaction rate would be increased by a factor of ____
...
6
c
...
18
d
...
Consider the following rate data for the reaction below at a particular temperature
...
10 M
0
...
20 M

Initial [B]
0
...
60 M
0
...
20  105 Ms1
1
...
64  104 Ms1

The reaction is ____ order in A and ____ order in B
...
third; first
c
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second; second
d
...
A troublesome reaction that is responsible in part for acid rain is
SO3 + H2O  H2SO4
Rate data have been determined at a particular temperature for the reaction in which all reactants and
products are gases
...
35 M
0
...
35 M
0
...
150
0
...
300
1
...
35 M
0
...
70 M
0
...

a
...
rate = k[SO3]2[H2O]2

c
...
rate = k[SO3][H2O]2

_D___ 20
...
The rate-law expression is rate =
k[NO]2[H2]
...
)
2NO(g) + 2H2(g)  N2(g) + 2H2O(g)
Experiment
1
2
3

Initial [NO]
0
...
0040 M
0
...
4
...
0
...
0060 M
0
...
0030 M

Initial Rate of Reaction (Ms1)
7
...
3  105
6
...
22 M2s1
d
...
3  102 M2s1

_D___ 21
...
3  102 min1 at 57 K
...
61 min
b
...
1200 min
d
...
The half-life of the zero order reaction below is 0
...
If the initial concentration of A is 3
...
1
...
1
...
3
...
0
...
The decomposition of dinitrogen pentoxide obeys the rate-law expression rate = 0
...
If the
initial concentration of N2O5 is 0
...
6 minutes?
N2O5  N2O3 + O2
a
...
13 M
b
...
028 M
_B___ 24
...
first
b
...
0
...
0
...
What is the kinetic order of the reaction?
c
...
negative one

_B___ 25
...
Reactant molecules must absorb energy to c
...

properly to form products
...
All reactant collisions result in product
d
...

formation
...
Given the following potential energy diagram for the one-step reaction
X+YZ+R

The arrow "c" represents the ____
...
activation energy for the reverse reaction
b
...
activation energy for the forward reaction
d
...
Consider the hypothetical reaction shown below
...

B
B2
B
A

+
+
+
+

B  B2
A  AB + B
AB  AB2
2B  AB2

slow
fast
fast
overall

Which one of the following statements must be true? The reaction is ____
...
second order in B and second order
c
...
first order in A and first order overall
d
...
Reaction rates increase with increasing temperature because ____
...
a greater fraction of molecules possess the c
...
larger molecules collide more frequently d
...
Suppose the activation energy of a certain reaction is 250 kJ/mol
...
(The universal gas constant = 8
...
)

a
...
067
b
...
15
...
3  1029

__D__ 30
...
64  102 s1 at 25C, and the activation energy is 74
...
Calculate k at 50C
...
0
...
0
...
1
...
0

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