Title: CHE2FCB Kinetics Assignment Quiz

Q: The reaction A -> P has order 0.

Which of the following strategies would correctly yield the rate constant, k?
- plot [A] vs time, k = -gradient
- plot [A]^2 vs time, k = -gradient
- plot ln[A] vs ln[time], k = gradient
- plot ln[A] vs time, k = -gradient
- plot 1/[A] vs 1/time, k = -gradient
- plot 1/[A] vs time, k = -gradient
- plot 1/[A] vs time, k = gradient
- plot 1/[A]^2 vs time, k = -gradient
- plot [A] vs time, k = intercept
- plot ln[A] vs time, k = intercept
A: plot ln[A] vs time, k = -gradient

Q: The reaction A -> P has order 0.

Which of the following strategies would correctly yield the rate constant, k?
- plot [A] vs time, k = -gradient
- plot [A]^2 vs time, k = -gradient
- plot ln[A] vs ln[time], k = gradient
- plot ln[A] vs time, k = -gradient
- plot 1/[A] vs 1/time, k = -gradient
- plot 1/[A] vs time, k = -gradient
- plot 1/[A] vs time, k = gradient
- plot 1/[A]^2 vs time, k = -gradient
- plot [A] vs time, k = intercept
- plot ln[A] vs time, k = intercept
A: plot [A] vs time, k = -gradient

Q: A chain polymerization reaction that uses initiator concentration 0.002 mol L^-1, and monomer concentration 0.50 mol L^-1 produces polymer chains of size 10^5. What would the chain size be if the initiator concentration was {ic} instead? (Give your answer in scientific notation with 2 decimal places: 4.95E5 for 4.95 x 10^5. )
A: 100000*(sqrt(20/{ic})) (formula; values not in the backup's text)

Q: When the reaction 3A + 2B -> C + 2D is carried out in 100 mls of solution, reactant B is consumed at a rate of 0.24 mol s^-1. What is the rate of reaction (Give answer to 2 decimal places)?
A: 1.2

Q: A chain polymerization reaction that uses initiator concentration 0.002 mol L^-1, and monomer concentration 0.50 mol L^-1 produces polymer chains of size 10^5. What would the chain size be if the initiator concentration was {ic} instead? (Give your answer in scientific notation with 2 decimal places: 4.95E5 for 4.95 x 10^5. )
A: 1000*(sqrt(20/{ic})) (formula; values not in the backup's text)

Q: Consider the mechanism shown below and state how many chain carriers are present (give your answer as an integer).

AH + B· -> A· + D

AH -> A· + H·

A· + H· -> AH

A· + B· -> P

A· -> B· + C
A: 3
Feedback ("3"): B, A, H

Q: Sulfur is released to the atmosphere as either hydrogen sulfide or sulfur dioxide, with the mechanism shown below. Both forms are toxic gases that are primary air pollutants, and can lead to acid rain formation.

O + H_2O -> 2 OH

HOSO_2 + OH -> H_2SO_4

O_3 + UV -> O_2 + O

H_2S + OH -> SH + H_2O

SH + O_2 -> OH +SO

SO + O_2 -> SO_2 + O

OH + SO_2 -> HOSO_2

How many chain carriers are present according to the mechanism?
A: 5
Feedback ("5"): OH, HOSO_2, SH, SO, O

Q: Consider the following mechanism comprised of elementary reactions:

A + B -> 2C ... k_1

2C -> A + B ... k_-1

C + 2A -> 2D ... k_2

D + 2B -> E + C ... k_3

What is correct expression for d[C]/dt ?
- 2k_1[A][B] - 2k_-1[C]^2 - k_2[C][A]^2 + k_3[D][B]^2 (2<i>k</i><sub>1</sub>[A][B] -2<i>k</i><sub>-1</sub>[C]<sup>2</sup> - <i>k</i><sub>2</sub>[C][A]<sup>2</sup> + <i>k</i><sub>3</sub>[D][B]<sup>2</sup>)
- k_1[A][B] -2k_-1[C]^2 - k_2[C][A] + k_3[D][B]
- k_1[A][B] -k_-1[C]^2 - k_2[C][A]^2 + k_3[D][B]^2
- 2k_1[C]^2 +2k_-1[C]^2 + k_2[C][A]^2 + k_3[E][C]
- k_1[A][B] +k_-1[C]^2 + k_2[C][A]^2 + k_3[D][B]^2
A: 2k_1[A][B] - 2k_-1[C]^2 - k_2[C][A]^2 + k_3[D][B]^2

Q: The following mechanism has been proposed for recombination of iodine atoms:

I + I -> I_2*, k_1 = [k1].0

I_2* -> I + I, k_-1 = [k-1].0

I_2* + M -> I_2, k_2 = [k2]

What is overall rate constant if k_1 = {k1}, k_-1 = {k-1} and k_2 = {k2}?
A: ({k1}/{k-1})*{k2} (formula; values not in the backup's text)
Feedback: Review Kinetics topic 4 (Mechanisms & complex reactions) - and in particular the section on pre-equilibrium approximation.

Q: The reaction A -> P has order 2.

Which of the following strategies would correctly yield the rate constant, k?
- plot [A] vs time, k = -gradient
- plot [A]^2 vs time, k = -gradient
- plot ln[A] vs ln[time], k = gradient
- plot ln[A] vs time, k = -gradient
- plot 1/[A] vs 1/time, k = -gradient
- plot 1/[A] vs time, k = -gradient
- plot 1/[A] vs time, k = gradient
- plot 1/[A]^2 vs time, k = -gradient
- plot [A] vs time, k = intercept
- plot ln[A] vs time, k = intercept
A: plot 1/[A] vs time, k = gradient

Q: At 1100 K, acetic acid decomposes via 2 competing, first order reactions:

CH_3COOH -> CH_4 + CO_2,   k_1 = {k1} s^-1

CH_3COOH -> CH_2=C=O + H_2O,    k_2 = {k2} s^-1

What would be the half-life (in seconds) of acetic acid at this temperature?
A: 0.693147181/({k1}+{k2}) (formula; values not in the backup's text)

Q: In a chain polymerization reaction, what would be the expected outcome if both initiator and monomer concentrations were halved?
- Propagation rate decreases to 50%, chain size decreases to 50% of initial values
- Propagation rate decreases to 71%, chain size decreases to 71% of initial values
- Propagation rate decreases to 35%, chain size decreases to 71% of initial values
- Propagation rate decreases to 50%, chain size increases to 141% of initial values
- Propagation rate increases to 71%, chain size increases to 141% of initial values
A: Propagation rate decreases to 35%, chain size decreases to 71% of initial values

Q: Label each of following main reaction paths for the release of sulfur to the atmosphere with a single letter: i (for initiation), p (for propagation), b (for branching) or t (for termination).
- O + H_2O -> 2 OH | b
- HOSO_2 + OH -> H_2SO_4 | t
- O_3 + UV -> O_2 + O | i
- H_2S + OH -> SH + H_2O | p
- SH + O_2 -> OH +SO | b
- SO + O_2 -> SO_2 + O | b
- OH + SO_2 -> HOSO_2 | p

Q: Consider the following mechanism comprised of elementary reactions:

A + B -> 2C ... k_1

2C -> A + B ... k_-1

C + 2A -> 2D ... k_2

D + 2B -> E + C ... k_3

What is correct expression for d[B]/dt ?
- k_1[A][B] – k_-1[C]^2 + k_3[D][B]
- –k_1[A][B] + k_-1[A][B] - k_3[D][B]^2
- –k_1[A][B] + 2k_-1[C]^2 - 2k_3[D][B]^2
- k_1[A][B] + k_-1[C]^2 + k_3[D][B]^2
- –k_1[A][B] + k_-1[C]^2 - 2k_3[D][B]^2
A: –k_1[A][B] + k_-1[C]^2 - 2k_3[D][B]^2

Q: Consider the following mechanism comprised of elementary reactions:

A + B -> 2C ... k_1

2C -> A + B ... k_-1

C + 2A -> 2D ... k_2

D + 2B -> E + C ... k_3

What is correct expression for d[A]/dt ?
- k_1[A][B] – k_-1[C]^2 + k_2[C][A]
- –k_1[A][B] + k_-1[C]^2 - 2k_2[C][A]^2
- –k_1[A][B] + 2k_-1[C]^2 - 2k_2[C][A]^2
- k_1[A][B] + k_-1[C]^2 + k_2[C][A]^2
- –k_1[A][B] + k_-1[A][B] - k_2[C][A]^2
A: –k_1[A][B] + k_-1[C]^2 - 2k_2[C][A]^2

Q: The decomposition of a gaseous sample of thioketene, H_2C=C=S, follows a rate law with order 2. The half-life is 400 s when the pressure of thioketene is 600 Pa, so what is the half-life when the when the pressure is 150 Pa?

_______________ s
A: 1600

Q: If a rate constant has units mol L-1 s-1, what is the overall order of the reaction?
- zero order
- order 1/2
- 1st order
- 2nd order
- 3rd order
- order 1.5
A: zero order

Q: Assume the reaction 2Fe^3+ + Sn^2+ -> 2Fe^2+ + Sn^4+

has a rate law v = k[Fe^3+][Sn^2+]

with rate constant, k = 0.70 mol^-1 L s^-1. If the initial concentrations are 0.60 mol L^-1 for Fe^3+, and 0.50 mol L^-1for Sn^2+, at what rate is Fe3+ consumed (in mol L^-1 s^-1)? Quote your answer to 2 decimal places.
A: 0.42

Q: Label each of following main reaction paths with a single letter: i (for initiation), p (for propagation), b (for branching) or t (for termination).
- AH + B· -> A· + D | p
- AH -> A· + H· | i
- A· + H· -> AH | t
- A· + B· -> P | t
- A· -> B· + C | p
Also offered: b