Ch 14 equations

Question 1

The following data were obtained in a kinetics study of the hypothetical reaction A + B + C→products.

zero-order
first-order
second-order
third-order
impossible to tell from the data given

Answer 1

C

Question 2

Which of the following units are consistent with the units of the reactionratein a first order reaction?
M/min
1/min
1/M * min
1/M2 * min
min/M

Answer 2

A

Question 3

For a certain overall second-order reaction with the general formaA→products, the initial rate of reaction is 0.50 M·s−1when the initial concentration of the reactant is 0.27M. What is therate constantfor this reaction?
0.039 M–1·s−1
6.9 M–1·s−1
0.50 M–1·s−1
0.54 M–1·s−1
25 M–1·s−1

Answer 3

b.

Question 4

The average rate of disappearance of ozone in the following reaction is found to be 7.01× 10–3atm/s.
4.67 × 10–3atm/s
7.01 × 10–3atm/s
16.4 × 10–3atm/s
172 × 10–3atm/s
10.5 × 10–3atm/s

Answer 4

e.

Question 5

The rate constant for a first-order reaction is 1.7×10–2s–1at 676 K and 3.9×10–2s–1at 880K. Determine the activation energy of the reaction. (R= 8.314 J/K⋅mol)
8.6 kJ/mol
8.7 kJ/mol
26 kJ/mol
2400 kJ/mol
21 kJ/mol

Answer 5

e.

Question 6

For a certain reaction of the general formaA→products, a plot of the experimental data of1/[A] versus time is linear. What is the reaction order with respect to the reactant (A)?Second-order
First-order
Zero-order
Third-order
Fourth

Answer 6

a.

Question 7

Given the initial rate data for the reaction A + B→C, determine the rate expression for the reaction
0.0344 0.160 2.11×10–2

Answer 7

Not a

Question 8

What is the half-life of the first-order reaction if it takes 4.4×10–2seconds for a concentration to decrease from 0.50 M to 0.20 M?
2.5×10–2s
3.3×10–2s
1.6 s
21 s
27 s

Answer 8

b.

Question 9

Calculate the activation energy, Ea, for
N2O5(g) → 2 NO2(g) + 1/2 O2(g)
given k (at 45.0 °C) = 5.79 × 10–4 s–1 and k (at 60.0 °C) = 3.83 × 10–3 s–1. (R = 8.314 J/K⋅mol)
0.256 kJ/mol
2.83 kJ/mol
31.1 kJ/mol
111 kJ/mol
389 kJ/mol

Answer 9

d.

Question 10

The rate constant for a reaction at 40.0°C is exactly 6 times that at 20.0°C. Calculate the Arrhenius energy of activation for the reaction. (R = 8.314 J/K⋅mol)
6.00 kJ/mol
8.22 kJ/mol
68.3 kJ/mol
14.9 kJ/mol
none of these

Answer 10

c.

Question 11

For the formation of 1 mol of nitrosyl chloride at a given temperature, ΔrH = –37 kJ/mol.
NO(g) + ½ Cl2(g) → NOCl(g)

The activation energy for this reaction is 81 kJ/mol. What is the activation energy for the reverse reaction?

81 kJ/mol
44 kJ/mol
118 kJ/mol
–37 kJ/mol
–118 kJ/mol

Answer 11

c.

Question 12

At a given temperature, a first-order reaction has a rate constant of 2.1 × 10–3 s–1. How long will it take for the reaction to be 25% complete?
660 s
2100 s
1500 s
59 s
140 s

Answer 12

not c. or a.

Question 13

Given the initial rate data for the reaction A + B → C, determine the rate expression for the reaction.

[A], M [B], M Δ[C]/Δt (initial) M/s

0.0418

0.122

2.73 × 10–4

Answer 13

b.

Question 14

Hydrogen peroxide decomposes into water and oxygen in a first-order process.
H2O2(aq) → H2O() + 1/2 O2(g)
At 20.0 °C, the half-life for the reaction is 3.92 × 104 seconds. If the initial concentration of hydrogen peroxide is 0.52 M, what is the concentration after 7.00 days?
1.2 × 10-5 M
0.034 M
0.074 M
0.22 M
0.52 M

Answer 14

a.

Question 15

The rate constant at 366 K for a first-order reaction is 7.7 × 10–3 s–1 and the activation energy is 15.9 kJ/mol. What is the value of the frequency factor, A, in the Arrhenius equation? (R = 8.314 J/K⋅mol)
0.0047 s–1
0.70 s–1
0.93 s–1
1.1 s–1
1.4 s–1

Answer 15

e.

Question 16

The reaction, A + 2B → B2 + A, proceeds by the following mechanism: (A is a catalyst.)
A + B → AB (slow)
AB + B → B2 + A (fast)
What is the rate law expression for this reaction?

Rate = k[A]
Rate = k[B]
Rate = k[A][B]
Rate = k[A][B]2
Rate = k[A]2[B]

Answer 16

c.

Question 17

The rate constant for a particular reaction is 0.0020 s−1. What is the overall order of this reaction?
0
1
2
3
4

Answer 17

a.

Question 18

The decomposition of phosphine, PH3, follows first-order kinetics.
4 PH3(g) → P4(g) + 6 H2(g)
The half-life for the reaction at 550 °C is 81.3 seconds. What percentage of phosphine remains after 195 seconds?
2.2%
9.8%
19%
42%
58%

Answer 18

c.

Question 19

Given the initial rate data for the reaction A + B → C, determine the rate expression for the reaction.

[A], M

[B], M

Δ[C]/Δt (initial) M/s

0.215

0.150

5.81 × 10–4

Answer 19

e.

Question 20

The Arrhenius equation, , relates the rate constant of reaction and temperature. A plot of ____ versus 1/T will yield a straight line with a slope of –Ea/R.
k2/k1

–Ea

ln(k)

1/RT

Answer 20

c.

Question 21

Assume the reaction below
2 NO(g) + O2(g) → 2 NO2(g)
proceeds via the following rate expression:

Which of the following statements concerning the above chemical reaction and rate equation is/are CORRECT?
1. The reaction is second-order with respect to NO.
2. The rate of disappearance of O2 is two times the rate of appearance of NO2.
3. According to the balanced chemical equation, the reaction is fifth-order overall.

Answer 21

a.

Question 22

For the reaction provided, the rate of disappearance of I–(aq) at a particular time and concentration is 2.4 × 10–3 mol/L·s.
IO3–(aq) + 5I–(aq) + 6H+(aq) → 3I2(aq) + 3H2O(l)

What is the relative rate of appearance of I2(aq)?

Group of answer choices

4.0 × 10–3 mol/L·s

7 × 10–3 mol/L·s

–1 × 10–3 mol/L·s

1 × 10–3 mol/L·s

7 × 10–3 mol/L·s

Answer 22

d.

Question 23

Given the initial rate data for the reaction A + B → C, determine the rate expression for the reaction.

[A], M

[B], M

Δ[C]/Δt (initial) M/s

0.0344

0.160

2.11 × 10–2

Answer 23

b.

Question 24

Given the initial rate data for the decomposition reaction,
A → B + C
determine the rate expression for the reaction.

[A], M

–Δ[A]/Δt M/s

0.084

12.4 × 10–6

Answer 24

a.

Question 25

For the first-order decomposition of N2O5 at a high temperature, determine the rate constant if the N2O5 concentration decreases from 1.04 M to 0.62 M in 375 seconds.
Group of answer choices

5.99 × 10–4 s–1

1.59 × 10–3 s–1

1.74 × 10–3 s–1

1.38 × 10–3 s–1

1.94 × 102 s–1

Answer 25

not b. or c.

Question 26

Given the initial rate data for the reaction A + B → C, determine the rate expression for the reaction.

[A], M

[B], M

Δ[C]/Δt (initial) M/s

0.0418

0.122

2.73 × 10–4

answers:

^[C]/^t = 5.35 X 10^-2 M^-2s^-1 [A][B]
ect.

Answer 26

c.

Question 27

A first-order reaction is 40.0% complete at the end of 48.6 minutes. What is the value of the rate constant?
1.89 × 10–2 min–1
1.05 × 10–2 min–1
53.0 min–1
95.1 min–1
none of these

Answer 27

b.

Question 28

The Arrhenius equation, expresses the dependence of the rate constant on the reaction temperature. The slope of a plot of ln(k) versus 1/T is equal to

Answer 28

e.

Question 29

The reaction A → B follows first-order kinetics with a half-life of 21.7 hours. If the concentration of A is 0.023 M after 48.0 hours, what was the initial concentration of A?
Group of answer choices

0.0050 M

0.051 M

0.51 M

0.11 M

2.0 M

Answer 29

d.

Question 30

According to the equation below, nitrosyl chloride is produced from the reaction of nitrogen monoxide and chlorine:

Answer 30

d.

Question 31

What is the overall order of the reaction NO(g) + O3(g) → NO2(g) + O2(g) if the reaction proceeds via the rate expression given below.

Group of answer choices

Zero-order

First-order

Second-order

Third-order

Fourth-order

Answer 31

c.

Question 32

For a certain reaction of the general form aA → products, the experimental data plotted as [A] versus time is linear. The slope of this plot must equal
Group of answer choices

–1.

the negative of the rate constant.

one over the rate constant.

the rate constant.

1.

Answer 32

b.

Question 33

The decomposition of formic acid follows first-order kinetics.
HCO2H(g) → CO2(g) + H2(g)
The half-life for the reaction at 550 °C is 24 seconds. How many seconds does it take for the formic acid concentration to decrease by 87.5%?
Group of answer choices

24 s

36 s

48 s

72 s

96 s

Answer 33

not b. or c.

Question 34

A second-order reaction starts with an initial concentration of 0.100 mol/L of the reactant. If the rate constant is 1.4 × 10–2 L/mol·s, what is the time required to decrease the initial concentration to 0.050 mol/L?
2A → B rate = k[A]2
Group of answer choices

710 s

1100 s

49.5 s

3.57 s

2100 s

Answer 34

a.

Question 35

In a first-order reaction, the half-life is 133 minutes. What is the rate constant?
Group of answer choices

1.25 × 10–4 s–1

5530 s–1

0.313 s–1

5.21 × 10–3 s–1

8.68 × 10–5 s–1

Answer 35

e.

Question 36

For the second-order reaction below, the initial concentration of reactant A is 0.24 M. If the rate constant for the reaction is 1.5 × 10–2 M–1s–1, what is the concentration of A after 265 seconds?
2A → B + C rate = k[A]2
Group of answer choices

0.12 M

0.19 M

0.95 M

4.0 M

5.2 M

Answer 36

not b. or c. or a.

Question 37

The reactants A and B are mixed, and the reaction is timed until a color change occurs. The data are as follows:

Answer 37

a.

Question 38

A first-order chemical reaction is observed to have a rate constant of 24 min–1. What is the corresponding half-life for the reaction?
Group of answer choices

1.7 s

1.7 min

35 min

2.5 s

34.3 s

Answer 38

a.

Question 39

The rate constant of a first-order decomposition reaction is 0.0147 s–1. If the initial concentration of reactant is 0.178 M, what is the concentration of reactant after 30.0 seconds?
Group of answer choices

8.72 × 105 M

0.0645 M

0.115 M

0.0785 M

0.643 M

Answer 39

c.