Unit 5 · Kinetics
Lesson 42 of 91

5.5 Collision Model

01Effective collisions

Particles react only if they collide with enough energy (≥ activation energy) and the right orientation.

Raising T increases both collision frequency and, much more importantly, the fraction of collisions above Ea.

02Notebook box

Higher T → more molecules past Ea on the Maxwell–Boltzmann curve → k increases.

Worked example: Why does refrigeration slow spoilage? Fewer collisions exceed Ea.

Key takeaways
  • ✦Energy + orientation.
  • ✦Temperature raises fraction above Ea.
  • ✦Most collisions don't react.
Quick check

Did it stick?

1.A collision fails despite high energy. Likely cause?

2.Main reason rate rises with T?

3.Activation energy is…