Collison Theory + Reaction Rate

What is collision theory?

What are the three points of collision theory?

What is reaction rate?

What are the factors affecting reaction rate?

• Temperature

• Concentration

• Pressure

• State of Sub - Division

• Catalyst

Temperature - Explained

• As temp increases, reaction rate increases

• A greater proportion of particles have sufficient energy to overcome the activation energy barrier

• Particles have a higher average kinetic energy and move faster, resulting in a higher frequency of collisions, thus resulting in a higher frequency of successful collisions

Concentration - Explained

• As concentration increases, reaction rate increases

• A greater number of particles in a given volume leads to a higher frequency of collisions, thus resulting in a higher frequency of succesful collisions

Pressure (Gases Only) - Explained

• As pressure increases, rate of reaction increases

• Gas Pressure can be increased by:

  • Adding more gas (volume does not change)

  • Decreasing the volume

• More particles in a given volume leads to a higher frequency of collisions, thus resulting in a higher frequency of successful collisions

• Gas pressure is caused when gas particles hit the walls of their container. The more often the particles hit the walls, and the faster they are moving when they do this, the higher the pressure

State of Subdivision - Explained

• The smaller the particle size, the greater the surface area is for a given mass of particles

• The result of an increase in surface area is an increase in the frequency of collisions, therefore increasing chance of successful collisions, and the reaction rate

Catalysts

• A catalyst is a substance that increases the rate of reaction without being consumed or produced

• A catalyst provides an alternative reaction pathway with a lower activation energy

• A lower activation energy means more particles have sufficient energy to react; thus, proportion of effective collisions will be higher