| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: Describe practical methods for investigating the rate of a reaction including change in mass of a reactant or a product and the formation of a gas |
Learning Objective/s:
- Describe two practical methods for measuring reaction rate (mass change and gas‑volume).
- Explain how to calculate the rate from mass loss/gain or gas volume change.
- Analyse the effect of variables such as concentration, temperature, surface area and catalyst on reaction rate using experimental data.
- Design a simple investigation to explore one variable affecting the rate.
|
Materials Needed:
- Digital balance
- Reaction vessels (beakers, conical flasks)
- Solid reactants (magnesium ribbon, zinc granules)
- Dilute hydrochloric acid
- Gas syringe or eudiometer
- Stop‑watch
- Thermometer and water bath
- Safety goggles and gloves
|
Introduction:
Begin with a quick demonstration of magnesium reacting with acid, producing bubbles, to capture interest. Review students' prior understanding of collision theory and how reaction rate is expressed. Explain that today they will learn how to quantify rates by measuring mass changes and gas evolution, and will be able to design investigations to explore influencing factors.
|
Lesson Structure:
- Do‑now (5') – Students answer a short question on factors affecting reaction rate.
- Mini‑lecture (10') – Explain the concepts of rate, the mass‑change method and the gas‑volume method, using diagrams.
- Demonstration (10') – Perform the Mg + HCl experiment, record mass at 30 s intervals, discuss data collection.
- Guided practice (15') – In pairs, set up the Zn + HCl gas‑syringe experiment, record volume every 10 s for 2 min, plot the data.
- Data analysis (10') – Calculate rates from graph slopes, compare the two methods and discuss sources of error.
- Investigation planning (10') – Groups choose a variable (e.g., concentration) and outline a simple investigation using one of the methods.
|
Conclusion:
Summarise that reaction rates can be measured by tracking mass loss or gas volume and that the slope of a graph gives the quantitative rate. Ask each student to write one key takeaway on an exit slip. For homework, assign a short report designing an experiment to test the effect of temperature on the rate using the mass‑change method.
|