Collision theory states that chemical reactions occur due to collisions between reactant particles. For a reaction to take place, the particles must collide with sufficient energy. Factors that increase collision frequency, such as higher concentration, pressure, and temperature, speed up reactions by making collisions between particles more common and energetic.

1. Summary

2. Collision Theory
• Reaction takes place when
particles collide.
Effective Collision
• Particles must collide with
sufficient energy for reactions
to occur

3. Collision Theory
• More frequent collisions => Faster
reaction
• Particles have higher energy => Faster
reaction

4. Factors Affecting Speed
of Reaction
1) Concentration
High concentration
• Particles are closer together
• Hence, they collide more
frequently
• Faster reaction

5. Factors Affecting Speed
of Reaction
2) Pressure
Pressure is increased
• Particles are squeezed closer
together
• Hence, they collide more
frequently
• Faster Reaction

6. Factors Affecting Speed
of Reaction
3) Temperature
Temperature is increased
• Particles have higher energy when
they collide
• Move faster and hence collide
more frequently
• Faster Reaction

7. Factors Affecting Speed
of Reaction
3) Temperature
Temperature is increased
• Particles have higher energy when
they collide
• Move faster and hence collide
more frequently
• Faster Reaction