Topic: Chemical Reactions – Rate of Reaction
Lesson 1: Collision Theory and Activation Energy
| Section | Details |
|---|---|
| Objective | Describe collision theory in terms of: (a) number of particles per unit volume, (b) frequency of collisions, (c) kinetic energy of particles, (d) activation energy (Ea). |
| Activities | – Starter (5 mins): Demonstrate a simple reaction (e.g., effervescence of Alka-Seltzer in water) and ask: “What causes the reaction to happen faster or slower?” – Main (25 mins): 1. Explain collision theory and its factors: particle concentration, collision frequency, kinetic energy, and activation energy. 2. Use diagrams or animations to visualize collisions. 3. Relate activation energy to the need for sufficient energy to overcome the reaction barrier. – Plenary (10 mins): Students summarize collision theory using a diagram with labeled components (particles, collisions, energy). |
| Resources | Animation or videos on collision theory, diagrams, simple reaction demonstrations, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Write a paragraph explaining how activation energy affects the rate of a reaction. |
| Assessment | Worksheet: Identify factors affecting collision frequency and activation energy in scenarios. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/20 Q4(a) – Describing collision theory and activation energy. |
Lesson 2: Effect of a Catalyst on Reaction Rates
| Section | Details |
|---|---|
| Objective | State that a catalyst increases the rate of a reaction by decreasing the activation energy (Ea) and is unchanged at the end of the reaction. |
| Activities | – Starter (5 mins): Ask: “Why do we add catalysts in industrial processes? How do they work?” – Main (25 mins): 1. Define catalyst and explain how it lowers activation energy. 2. Show an energy profile diagram with and without a catalyst. 3. Discuss examples of catalysts in industry (e.g., iron in Haber process, enzymes in biological systems). – Plenary (10 mins): Students label an energy profile diagram showing the effect of a catalyst. |
| Resources | Diagrams of energy profiles, videos of catalyzed reactions, worksheets with guided problems. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Research and write about one industrial process that uses a catalyst, explaining its role. |
| Assessment | Worksheet: Compare energy profiles with and without a catalyst, and explain the differences. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/21 Q4(b) – Explaining the role of catalysts in reactions. |
Lesson 3: Factors Affecting Rate of Reaction
| Section | Details |
|---|---|
| Objective | Describe and explain the effects on reaction rates of: (a) changing concentration, (b) changing pressure, (c) changing surface area, (d) changing temperature, (e) adding/removing a catalyst, using collision theory. |
| Activities | – Starter (5 mins): Ask: “Why do some reactions happen faster than others?” – Main (25 mins): 1. Explain how each factor affects reaction rate using collision theory. 2. Conduct simple demonstrations (e.g., powdered vs. solid reactants, temperature effect on effervescence). 3. Relate observations to collision frequency, kinetic energy, and activation energy. – Plenary (10 mins): Students complete a table summarizing the effect of each factor on the rate of reaction. |
| Resources | Reaction setups (e.g., marble chips and HCl), thermometer, powdered and solid reactants, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Write a short explanation of how temperature and surface area affect reaction rates. |
| Assessment | Quiz: Predict the effect of changes in concentration, pressure, and temperature on reaction rates. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/20 Q4(c) – Factors affecting reaction rates using collision theory. |
Lesson 4: Practical Methods for Investigating Reaction Rates
| Section | Details |
|---|---|
| Objective | Describe and evaluate practical methods for investigating reaction rates, including change in mass and gas formation. |
| Activities | – Starter (5 mins): Show a reaction producing gas (e.g., HCl and marble chips) and ask: “How can we measure how fast this reaction happens?” – Main (25 mins): 1. Discuss methods: measuring mass loss, volume of gas produced, and time for color changes. 2. Conduct a simple experiment (e.g., reaction of Mg with HCl, collecting hydrogen gas in a syringe). 3. Discuss variables affecting results and how to ensure accuracy. – Plenary (10 mins): Students write a method for investigating a reaction rate, including equipment and variables. |
| Resources | Reaction setups, gas syringes, scales, stopwatches, worksheets for experiment planning. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Plan an investigation to compare the rate of reaction using powdered and solid marble chips. |
| Assessment | Worksheet: Evaluate methods for measuring reaction rates and identify potential errors. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/21 Q5(a) – Evaluating methods for measuring reaction rates. |
Lesson 5: Interpreting Rate of Reaction Data
| Section | Details |
|---|---|
| Objective | Interpret data, including graphs, from rate of reaction experiments. |
| Activities | – Starter (5 mins): Show a graph of gas volume vs. time and ask: “What can we learn from this graph?” – Main (25 mins): 1. Teach students how to interpret rate of reaction graphs (e.g., steepness of the curve, flat portions). 2. Relate graph features to factors affecting the rate (e.g., faster initial rate due to higher concentration). 3. Practice analyzing graphs and data sets from reaction experiments. – Plenary (10 mins): Students draw a graph for a given set of reaction data and label key features. |
| Resources | Graph paper, example data sets, reaction rate graphs, worksheets for graph analysis. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Analyze a provided reaction graph and answer questions about rate changes over time. |
| Assessment | Worksheet: Interpret data and graphs for different reaction rate experiments. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/19 Q5(b) – Interpreting graphs and data for reaction rates. |
Notes for Teachers:
- Use hands-on experiments to help students connect theoretical concepts to practical observations.
- Emphasize the application of collision theory when explaining factors affecting reaction rates.
- Provide ample practice with data interpretation and graphing skills.
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