Test Questions

Question 1

The Kinetics of the reduction of persulfate with iodide was studied in an aqueous
solution.
S2O8 2⁻(aq) + 3 I⁻(aq) → 2 SO4 2⁻(aq) + I3- (aq)

(A) What is the average reaction rate between 1 and 3 s? Enter your answer in M/s as a decimal
fraction with one significant figure.

Question 2

The Kinetics of the reduction of persulfate with iodide was studied in an aqueous
solution.
S2O8 2⁻(aq) + 3 I⁻(aq) → 2 SO4 2⁻(aq) + I3- (aq)

(B) By what amount did the concentration of iodide decrease between 1 and 3 s? Enter your
answer in M with two significant figures.

The rate of the reaction was measured for different sets of reactant concentrations.

Question 3

(c) Determine the order of the reaction in each reactant and calculate the rate constant

Question 4

Milk spoils about three times faster at ambient temperature (+25 degrees Celsius) than in the
fridge (+5 degrees Celsius). Estimate the activation energy of the reaction responsible for milk going bad.

Question 5

Given the following proposed mechanism, predict the rate law for the overall reaction.
A2 + 2B → 2AB (overall reaction)
Mechanism
A2 ⇌ 2A fast
A + B → AB slow

A) Rate = k[A][B]
B) Rate = k[A2][B]
C) Rate = k[A2][B]1/2
D) Rate = k[A2]
E) Rate = k [A2]
1/2[B]

Question 6

In aqueous solutions, hypobromite undergoes disproportionation:
3 BrO– → 2 Br– + BrO3–
A) What is the order of the reaction with respect to hypobromite?

Question 7

In aqueous solutions, hypobromite undergoes disproportionation:
3 BrO– → 2 Br– + BrO3–
(B) Determine the initial concentration of hypobromite.

Question 8

In aqueous solutions, hypobromite undergoes disproportionation:
3 BrO– → 2 Br– + BrO3–
(C) What is the half-lifetime of hypobromite in this reaction?

Question 9

In aqueous solutions, hypobromite undergoes disproportionation:
3 BrO– → 2 Br– + BrO3–
(D) Calculate the concentration of hypobromite at 70 s.

Question 10

Consider the following equilibrium:
CO(g) + H2O(g) ⇌ CO2(g) + H2(g) ΔrHo = –41 kJ/mol
KP = 7.7 × 10-5 at 850 degrees Celsius
A closed chamber initially contains 5.00 atm H2O and 5.00 atm CO at 850 degrees Celsius.

A) What are the partial pressures of the reactants and the products when the system reaches its equilibrium?

Question 11

(B) Indicate whether each of the following will shift the equilibrium toward the products (→), toward the reactants (←), or leave it unchanged:
1. Raising the temperature in the chamber;
2. Increasing the total pressure in the chamber by shrinking the volume by a factor of 2;
3. Adding Ar (inert gas) into the chamber;
4. Adding more steam to the system;
Removing H2 from the system;
5. Adding CO2 to the system;
Introducing a catalyst into the system.