Initial rate of reaction data is given in the next question for the following re
ID: 983456 • Letter: I
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Initial rate of reaction data is given in the next question for the following reaction:
2A + B C +D
The rate of reaction = k[A]x[B]y. What are x and y, that is, what is the order of reaction with respect to A and B?
Select one or more:
a. x =0
b. x = 0.5
c. x = 1
d. x = 2
e. y = 0
f. y = 0.5
g. y = 1
h. y = 2
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Determine the rate constant from the concentration-time dependence (The units for the initial rate of reaction are Ms-1):
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Consider the second-order decomposition of nitroysl chloride:
2NOCl(g) 2NO(g) + Cl2(g)
At 450 K the rate constant is 15.4 atm-1s-1. How much time (in s) is needed for NOCl originally at a partial pressure of 85 torr to decay to 19.9 torr?
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How much time (in s) is needed for NOCl originally at a concentration of 0.0149 M to decay to 0.0016 M?
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The decomposition of formic acid (see below) is measured at several temperatures.
HCOOH(g) CO2(g) +H2(g)
The temperature dependence of the first-order rate constant is:
T(K) . . . . k(s-1)
Calculate the activation energy, in kJ/mol.
Use all data points and do a linear regression using calculator or Excel. Do not pick 2 data points. This is less accurate and assumes all data points are equally qood.
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Calculate the pre-exponential term (in s -1).
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The activation energy for the isomerization ol cyclopropane to propene is 274 kJ/mol. By what factor does the rate of this reaction increase as the temperature rises from 235 to 286 oC? (The factor is the ratio of the rates.)
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A catalyst decreases the activation energy of a particular exothermic reaction by 22 kJ/mol, to 35 kJ/mol. Assuming that the mechanism has only one step, and that the products are 71 kJ lower in energy than the reactants, sketch approximate energy-level diagrams for the catalyzed and uncatalyzed reactions.
What is the activation energy for the uncatalyzed reverse reaction?
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Select one or more:
a. x =0
b. x = 0.5
c. x = 1
d. x = 2
e. y = 0
f. y = 0.5
g. y = 1
h. y = 2
Question 10
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Select one or more:
a. x =0
b. x = 0.5
c. x = 1
d. x = 2
e. y = 0
f. y = 0.5
g. y = 1
h. y = 2
Question 11
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Select one or more:
a. x =0
b. x = 0.5
c. x = 1
d. x = 2
e. y = 0
f. y = 0.5
g. y = 1
h. y = 2
i. Itermediate: O2
j. Itermediate: N2O4
k. Itermediate: O3
l. This rate law is consistent with the experimental one.
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Select one or more:
a. x =0
b. x = 0.5
c. x = 1
d. x = 2
e. y = 0
f. y = 0.5
g. y = 1
h. y = 2
i. Itermediate: O2
j. Itermediate: NO3
k. Itermediate: O3
l. Consistent
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Select one or more:
a. Reaction order at 310 K: 0
b. Reaction order at 310 K: 1
c. Reaction order at 310 K: 2
d. Reaction order at 315 K: 0
e. Reaction order at 315 K: 1
f. Reaction order at 315 K: 2
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What is the rate constant at 310 K? (Use SI units. For example, use seconds not minutes or hours.)
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Question 15
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What is the rate constant at 315K?
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Question 16
What is the activation energy (in J/mol)?
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Question 17
When formic acid is heated, it decomposes to hydrogen and carbon dioxide in a first-order decay:
HCOOH(g) CO2(g) + H2 (g)
The rate of reaction is monitored by measuring the total pressure in the reaction container.
Time (s) . . . Ptot (torr)
0 . . . . . . . . . 220
50 . . . . . . . . 324
100 . . . . . . . 379
150 . . . . . . . 408
200 . . . . . . . 423
250 . . . . . . . 431
300 . . . . . . . 435
At the start of the reaction (time = 0), only formic acid is present. What is the formic acid pressure (in torr) when the total pressure is 235? Hint: use Dalton's law of partial pressure and the reaction stoichiometry.
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Question 18
What is the rate constant (in s-1)? (To determine the rate, you must use a reactant concentration or pressure. Use the procedure of in the previous question to determine the HCOOH pressure as a function of the total pressure.)
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Question 19
What is the half-life (in s)?
Answer:
[A] [B] Init. Rate 0.020 0.15 0.055 0.035 0.15 0.096 0.050 0.35 0.75Explanation / Answer
Solution :-
Q1). 2A + B ----- > C + D
Therefore the rate law is
Rate = K [A]^2 [B]
So the value of the x= 2
And value of y= 1
Q2) using the concentration and the rate lets calculate the order of each reactant
Calculating the order with A
Rate 2 / rate 1 = ([A]2/[A]1)^m
0.096/0.055 = [0.035/0.020]^m
1.745 = 1.75 ^m
Log 1.745 = m* log 1.75
Log 1.745 / log 1.75 = m
m= 1
now lets calculate the order with B
rate 3/rate 2 = ([B]3/[B]2)^n
0.75/0.096 = [0.35/0.15]^n
7.8125 = 2.333^n
n= 2
so the order with B is second order
now lets write the rate law
Rate =K [A][B]^2
Lets calculate the rate constant
0.055 = K [0.020][0.15]^2
K = 0.055 / [0.020][0.15]^2
K= 122
So the rate constant = 122
Q3)
2NOCl ---- > 2NO + Cl2
Second order reaction
K = 15.4 atm s-1
Initial = 85 torr
Final = 19.9 torr
Tiem = ?
1/[A]t = 1/[A]o + K* t
1/(19.9/760) = (1/(85/760)) + 15.4 * t
38.19= 8.94+ 15.4 * t
( 38.19-8.94)/ 15. 4 = t
X= 1.9 s
So the time needed is 1.9 s
Q4) initial concentration [NOCl] =0.0149 M
Final = 0.0016 M
Time = ?
We know the rate constant = 15.4 atm s-1
1/[A]t = 1/[A]o + kt
1/0.0016 = (1/0.0149) + 15.4 * t
625 = 67.11 * 15.4 * t
625 – 67.11 /15.4 =t
36.2 s = t