Unit 5: Kinetics
Chemistry · Unit 5 · Paper 3

Kinetics unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1Paper 2Paper 3
Each paper is built from this unit’s 19 terms and is the same for everyone, so a teacher can assign “Unit 5, Paper 3” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.
Suggested time 31 min 28 points0/17 attempted
1

Rate law

2

Steady-state intermediates

3

Method of initial rates

4

Determining order graphically

5

Rate-determining step

6

Reaction mechanism

7

Zero-order kinetics

8

Pseudo-first-order conditions

9

Why order cannot be read from coefficients

10

Intermediate vs catalyst

11

Why a catalyst does not shift equilibrium

12

Collision theory

Short answer 1. Define or explain: Catalysis

3 pts

Short answer 2. Define or explain: First-order kinetics

3 pts

Short answer 3. Define or explain: Energy profile diagram

3 pts

Short answer 4. Define or explain: Activation energy

3 pts

Free response

4 pts

Ozone decomposes to oxygen according to 2 O₃(g) → 3 O₂(g). A proposed mechanism is: Step 1 (fast, reversible) O₃ ⇌ O₂ + O Step 2 (slow) O₃ + O → 2 O₂

(a) Show that the proposed mechanism is consistent with the overall balanced equation.

(b) Identify the intermediate in the mechanism, and justify your identification.

(c) Identify the molecularity of the rate-determining step.

(d) Explain why the observed rate of ozone decomposition decreases when the concentration of O₂ is increased.