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Paper 2

Rates of Reaction and Equilibrium

Both
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Collision theory diagram showing particle collisions

More frequent successful collisions = faster rate.

Key Facts

  • Increasing temperature increases rate but can reduce yield in exothermic systems.
  • Catalysts speed up both forward and reverse reactions.

Topics Covered

Rates of Reaction

What you need to know

  • Collision theory explains reaction rate.
  • Factors: temperature, concentration, surface area, catalyst.

Exam Tips

  • Use the phrase "more frequent successful collisions."

Equilibrium

What you need to know

  • Equilibrium is dynamic in a closed system.
  • Temperature changes shift equilibrium position.

Exam Tips

  • State whether the forward reaction is exo or endothermic.

Key Terms

Collision theory

Particles must collide with enough energy to react.

Equilibrium

Forward and reverse reactions occur at the same rate.

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Common Exam Questions

Explain why increased concentration increases rate.

3 marksmediumPaper 2

Model Answer

Particles are closer together, so collisions happen more often and more successful collisions occur.

What examiners want to see

  • Mention collisions.
  • Link to success rate.

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