Rate of Reactions

This note covers factors affecting reaction rates, the role of catalysts including enzymes and industrial catalysts, and methods to investigate reaction rates experimentally.

1. Factors Affecting Reaction Rates
  • 🔹 Concentration and Pressure:

    🔹 Increasing concentration or pressure increases reaction rate by causing more frequent collisions.

  • 🔹 Particle Size:

    🔹 Smaller particle size increases surface area, speeding up reactions.

  • 🔹 Temperature:

    🔹 Higher temperature increases kinetic energy, leading to more successful collisions and faster reactions.

2. Catalysts
  • 🔹 Definition:

    🔹 Catalysts speed up reactions without being consumed.

  • 🔹 Enzymes:

    🔹 Biological catalysts that increase reaction rates in living organisms.

  • 🔹 Activation Energy:

    🔹 Catalysts lower the activation energy needed, allowing reactions to proceed faster.

3. Industrial Catalysts
  • 🔹 Description:

    🔹 Certain compounds act as catalysts in industries to increase efficiency and reduce costs.

  • 🔹 Example:

    🔹 Haber process uses catalysts to synthesize ammonia.

4. Investigating Reaction Rates
  • 🔹 Experimental Variables:

    🔹 Vary concentration, pressure, temperature, particle size, or catalyst presence to measure effects on rate.

  • 🔹 Data Interpretation:

    🔹 Analyze changes in reaction time, product formation, or reactant disappearance to determine rate effects.

  • ⚠️ Catalysts are used up during the reaction; actually, catalysts remain unchanged.
  • ⚠️ Increasing concentration always increases reaction rate linearly; the relationship may vary depending on reaction order.
  • ⚠️ Temperature only affects reaction speed; it also affects the energy distribution of particles.

  • 👉 Explain how each factor affects reaction rate using collision theory.
  • 👉 Describe the role and benefits of catalysts in both biological and industrial contexts.
  • 👉 Outline experimental setups to investigate factors affecting reaction rates.
  • 👉 Practice interpreting graphs showing reactant concentration or product formation over time.

📚 Further Understanding