Chemical Reaction Kinetics Worksheet

Learning Objectives:

By the end of this worksheet, you will be able to: - Explain collision theory and its relation to chemical reactions - Interpret graphs showing temperature/concentration effects on reaction rate - Describe temperature's effect on particle kinetic energy - Explain how concentration affects collision frequency - Apply the concept of activation energy to chemical reactions

Part 1: Collision Theory Basics

1. Fill in the blanks: Collision theory states that for a chemical reaction to occur, reactant particles must ________ with each other with sufficient ________ and proper _________.

2. Which of the following statements about collision theory are TRUE? Circle all that apply.

a) Every collision between reactant particles leads to a reaction.

b) Particles must collide with enough energy to break existing bonds.

c) The orientation of the colliding particles doesn't matter.

d) Increasing the frequency of collisions typically increases reaction rate.

e) Collision theory only applies to gas-phase reactions.

3. Draw a simple diagram showing two particles:

a) Colliding with proper orientation that would lead to reaction

b) Colliding with improper orientation that would not lead to reaction

Part 2: Interpreting Reaction Rate Graphs

4. Study the graph below showing the effect of temperature on reaction rate:

Reaction   │            /
Rate       │           /
           │         /
           │       /
           │     /
           │   /
           │ /
           │/
           └──────────────
             Temperature

a) As temperature increases, what happens to the reaction rate? _____________

b) Is this relationship linear or non-linear? What does this tell you about how temperature affects reaction rate? _____________

5. Examine the graph showing the effect of concentration on reaction rate:

Reaction   │         /
Rate       │        /
           │       /
           │      /
           │     /
           │    /
           │   /
           │  /
           │ /
           │/
           └──────────────
             Concentration

a) Describe the relationship shown in this graph: _____________

b) If you doubled the concentration, would you expect the reaction rate to exactly double? Explain your reasoning: _____________

Part 3: Temperature and Kinetic Energy

6. The graph below shows the distribution of molecular kinetic energies at two different temperatures (T₁ and T₂, where T₂ > T₁):

Number    │    T₁     T₂
of        │     \     \
Molecules │      \     \
          │       \     \
          │        \     \
          │         \     \
          │          \     \
          │           \     \
          │            \     \
          │             \     \
          │              \     \
          └───────────────────────
                Kinetic Energy

a) What happens to the average kinetic energy of particles when temperature increases? _____________

b) How does the fraction of particles with energy above a certain threshold (like activation energy) change when temperature increases? _____________

c) Explain how this relates to reaction rate: _____________

Part 4: Concentration and Collision Frequency

7. Consider a chemical reaction between substances A and B:

a) If you triple the concentration of A, how will this affect the frequency of collisions between A and B molecules? Explain using collision theory: _____________

b) Draw a simple diagram comparing the particle distribution in a low concentration versus high concentration solution:

c) A student claims that increasing concentration makes particles move faster. Is this correct? Explain: _____________

8. For the reaction 2A + B → A₂B, complete the table below:

Change Made	Effect on Collision Frequency	Effect on Reaction Rate
Double [A]
Double [B]
Double both

Part 5: Activation Energy

9. The diagram below shows a potential energy diagram for a reaction:

Potential  │      *
Energy     │     / \
           │    /   \
           │   /     \
           │  /       \
           │ /         \
           │/           \
           │             \
           │              \
           │               \
           └─────────────────
           Reaction Progress

a) Label the activation energy (Ea) on the diagram.

b) Label the reactants and products.

c) Is this reaction exothermic or endothermic? How do you know? _____________

10. Application Questions:

a) Explain why a match must be struck before it will burn, even though the burning reaction is exothermic: _____________

b) Catalysts increase reaction rates without being consumed. Explain how catalysts affect activation energy and draw a simple energy diagram showing a catalyzed vs. uncatalyzed reaction: _____________

c) A chemical reaction proceeds twice as fast when the temperature is raised from 20°C to 30°C. Using collision theory, explain why the rate doesn't simply increase proportionally with the temperature change: _____________

Bonus Challenge:

Design an experiment to test how temperature OR concentration affects the rate of a simple reaction. Include: - Your hypothesis - Independent and dependent variables - Control variables - Basic procedure - How you would measure reaction rate - How you would analyze your data