1. As always… OWL Lon-Capa assignments Lecture videos Textbook Read
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2. Exam III
Thursday, December 6, 7:00-9:00 pm; rooms are on the website (same as Exam II).
Conflict: (12/6) 4:30-6:30 pm in 219 Greg; sign up in 1026 Chem Annex starting Friday
Conflict with conflict? me right away.
Review sessions: 1024 Chem Annex, 6-8 pm
Monday, December 3
Tuesday, December 4

3. Clicker Questions
Pure N2O3 was placed in a rigid vessel and allowed to decompose: 2N2O3(g)  2N2(g) + 3O2(g). The following data were collected in an experiment at a certain temperature. Determine:
the rate law of the reaction.
the first half-life for the reaction
the pressure of O2(g) at t = minutes
Time (min)
Ptotal (atm)
10.000
10.00
15.071
20.00
18.428
30.00
20.649
40.00
22.120
50.00
23.094

4. Rate Laws From Elementary Steps

5. Clicker Question
The experimental rate law for the decomposition of nitrous oxide (N2O) to N2 and O2 is rate = k[N2O]2. Two mechanisms are proposed:
I. N2O  N2 + O
N2O + O  N2 + O2
II. 2N2O N4O2
N4O2  2N2 + O2
Which of the following could be a correct mechanism?
a) Mechanism I with the first step as the rate-determining step.
b) Mechanism I with the second step as the rate-determining step as long as the first step is a fast equilibrium step.
c) Mechanism II with the second step as the rate-determining step if the first step is a fast equilibrium step.
d) None of the choices (a-c) could be correct.
e) At least two of the above choices (a-c) could be correct.

6. Chapter 15

7. Pseudo-Order Question
Determine the rate law and value of k given the following data.
2H2(g) + 2NO(g)  N2(g) + 2H2O(g)
EXPERIMENT #1 EXPERIMENT #2
TIME (sec) [NO] [NO] ________
x 10-2 M 1.00 x 10-2 M
x 10-3M 5.00 x 10-3 M
x 10-3 M 3.33 x 10-3 M
x 10-3 M 2.50 x 10-3 M
x 10-3 M 2.00 x 10-3 M
In experiment #1, [H2]0 = 10.0 M
In experiment #2, [H2]0 = 20.0 M