6.2.1

Collision Theory & Rate of Reaction

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Chemical Reactions: Collision Theory and Rate of Reaction

Reactions need particle collisions with sufficient energy and proper orientation. Rate rises with concentration or temperature, while catalysts lower Ea.

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What is collision theory?

  • Collision theory explains how chemical reactions occur when particles collide.
    • The theory states that particles must collide to react.
  • Collisions must have enough energy and proper orientation.
  • Collision theory helps us understand the rate of reaction.
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Number of particles per unit volume

  • Reaction rate depends on the number of particles per unit volume.
  • More particles in the same space mean more collisions occur.
  • Increasing concentration usually increases reaction rate.
    • Example: More hydrogen ions in acid speed up the metal reaction.
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Frequency of collisions between particles

  • Reaction rate increases with collision frequency.
    • Particles collide more often when they move faster.
    • Higher temperature makes particles move faster.
  • More frequent collisions give more chances for reactions.
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Kinetic energy and activation energy (Ea)

  • Particles need enough kinetic energy to overcome activation energy, Ea.
    • Activation energy is the minimum energy to start a reaction.
    • Only collisions with energy ≥ Ea cause reaction.
  • Increasing temperature raises kinetic energy, so more particles reach Ea.
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Activation energy and reaction control

  • Activation energy explains why some reactions are slow or fast.
    • Catalysts lower activation energy, speeding up reactions.
    • Without enough energy, particles bounce off without reacting.
  • Understanding Ea helps control reaction rates in industry.

Jump to other topics

1States of Matter

2Atoms, Elements & Compounds

3Stoichometry

4Electrochemistry

5Chemical Energetics

6Chemical Reactions

7Acids, Bases & Salts

8The Periodic Table

9Metals

10Chemistry of the Environment

11Organic Chemistry

11.1Formulae, Functional Groups & Terminology

11.2Naming Organic Compounds

11.3Fuels

11.4Alkanes

11.5Alkenes

11.6Alcohols

11.7Carboxylic Acids

11.8Polymers

12Experimental Techniques & Chemical Analysis

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