CHM152 Quiz 2a 25 Pts Spring 2019 Name:--'}<'---~--------rate = k
[A]t = -kt+ [A]o
rate = k[A] rate = k[A]2
R= 8.314 J/(mol•K)
1/[A]t= kt+ 1/[A]o t112 = [A]o/2k
ln[A]t= -kt+ ln[A]o
t112 = 0.693/k
In [ AL
[Alo
t112 = 1/k[A]o
=-kt
********SHOW ALL WORK TO RECEIVE CREDIT************
1. (6 Pts) The activation energy for the following first-order reaction is 122 kJ/mol.
N2Os(g) ➔ 2N0i(g) + 1hO2(g)
The value of the rate constant (k) is 1.35 10 -4 s-1 at 45°C. What is the value ofk at 10°C?
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2. (6 Pts) Calculate the activation energy, in kJ/mol, for the redox reaction
Sn2+ + 2Co3+ ➔ Sn4+ + 2Co2+.
Temp ( 0 C)
k {1/M·s)
2
3.12 10 3
27
27.0 10 3
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3. (4 Pts)
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The isomerization of cyclopropane to form propene is a first-order reaction.
H2C\ /CH2
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CH1
At 760 K, 85% of a sample of cyclopropane changes to propene in 59.0 min. Determine the rate constant for
this reaction at 760 K.
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******MORE QUESTIONS ON THE BACK*****
4. (5 Pts) A reaction was experimentally determined to follow the rate law, Rate= k[A] 2 where k = 0.456
s· 1M- 1 • Starting with [A]o = 0.500 M, how many seconds will it take for [A]t = 0.250 M?
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➔ C+ D
The reaction 2A + 2B
proceeds by this mechanism:
(equilibrium)
A2 + B ➔ X + C
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(rate determining)
X+ B➔ D
(rapid)
Write the rate equation for the reaction. You may want to first label any intermediates.
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CHM152 Quiz 2b 25 Pts Spring 2019 Name: _ _
rate = k[A] rate = k[A] 2
rate = k
R= 8.314 J/(mol•K)
[A]t =-kt+ [A)o
1/[A]t= kt+ 1/[A]o t112 = [A]o/2k
ln[A]t= -kt+ ln[A]o
t112 = 0.693/k
In [A],
t112 = 1/k[A]o
= -kt
[AL
********SHOW ALL WORK TO RECEIVE CREDIT************
1. (6 Pts) The activation energy for the following first-order reaction is 132 kJ/mol.
N2Os(g) ➔ 2NO2(g) + 1hO2(g)
The value of the rate constant (k) is 1.35 10 -4 s-1 at 55°C. What is the value ofk at 20°C?
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2. (6 Pts) Calculate the a · 10n energy, in kJ/mol, for the redox reaction
Sn2+ + 2Co3+ ➔ Sn4+ + 2Co2+.
Temp {°C}
k {1/M·s)
2
3.12 10 3
27
27.0 10 3
S-e-e.
3. (4 Pts)
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The isomerization of cyclopropane to form propene is a first-order reaction.
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At 760 K, 75% of a sample of cyclopropane changes to propene in 69.0 min. Determine the rate constant for
this reaction at 760 K.
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******MORE QUESTIONS ON THE BACK*****
4. (5 Pts) A reaction was experimentally determined to follow the rate law, Rate= k[A] 2 where k = 0.456
s- 1M- 1• Starting with [A]o = 0.500 M, how many seconds will it take for [A]t = 0.250 M?
5.(4 Pts)
The reaction 2A + 2B ➔ C + D proceeds by this mechanism:
2A +t A 2
A2 + B ➔ X + C
X+ B➔ D
(equilibrium)
(rate determining)
(rapid)
Write the rate equation for the reaction. You may want to first label any intermediates.