Lesson Plan: Rates of Reaction - Catalysts and Enzymes (LP0039)

Learning objectives

1. A catalyst is a substance that increases the rate of a reaction but remains chemically unchanged at the end of the reaction.
2. The decomposition of hydrogen peroxide with and without manganese(IV) oxide added, can be used to investigate the effect of catalysts on rate of reaction.
3. Enzymes are catalysts in biological systems.
4. The fermentation of sugar solution with and without yeast added, can be used to investigate the effect of enzymes on rate of reaction.

Resources

• Crocodile Chemistry 1.5 (or later)
• LF0039a "The decomposition of hydrogen peroxide"
• LF0039b "Fermentation"

Procedure

1. Ensure Crocodile Chemistry 1.5 (or later) is installed and the simulation files LF0039a and LF0039b are accessible.
2. Introduce and explain the learning objectives listed above.
3. Complete lesson activity LA0039.
4. Discuss the activity and the related points listed below.

Classroom discussion points

• Everyday examples of the uses of catalysts e.g. in catalytic converters in car exhausts and in the manufacture of ammonia in industry.
• Everyday examples of the uses of enzymes e.g. in saliva, baking and cheese making.
• Why adding a catalyst or an enzyme increases the rate of reaction. The activation energy of a reaction and the effect a catalyst or enzyme has on it.

Assessment

• Completion of lesson activity LA0039.
• Observation of the students at work and response to discussion work.

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