Year 10 Chem

Collision Theory

For a reaction to occur:

1. Particles must collide.

2. Particles must collide with enough energy by overcoming the activation energy barrier.

3. Particles must collide with the correct orientation.
   They need to hit each other in the right "alignment" for bonds to break and form.

Temperature

• Increasing temperature gives particles more kinetic energy.

• They move faster → collide more often and with more energy.

Result:

• Higher temperature = faster reaction

• Lower temperature = slower reaction

Concentration

Higher concentration = more frequent collisions = faster reaction

Particle Size (Surface Area)

• Smaller particles = faster reaction

• Larger pieces = slower reaction

• More particles are exposed → more chance for collisions.

Catalyst Present

• Speeds up a reaction

• Is not used up in the reaction

• Provides an alternative reaction pathway with lower activation energy

Effect on rate:

• More particles now have enough energy to successfully react → reaction speeds up.

Activation Energy

the minimum amount of energy required to start a chemical reaction