Collision theory

Collision theory

For a reaction to occur particles must collide, with sufficient energy

Activation energy

Minimum amount of energy to start a chemical reaction

Concentration

A measurement of how much solute exists within a certain volume of solvent

Increasing concentration increases rate because

More particles in the same volume = More frequent collisions

Gas pressure

the force that the gas exerts on the walls of its container

Increasing pressure increases rate because

More particles in a smaller volume = More frequent collisions

Increasing surface area increases rate because

More particles at the surface = More frequent collisions

Increasing temperature increases rate because

Particles have more energy AND more particles have at least the activation energy = More frequent collisions

Catalyst

Substance that speeds up the rate of a chemical reaction without being used up

Catalysts work by

Providing an alternate reaction pathway with lower activation energy

Increase rate of reaction

Increase temp, concentration, pressure, surface area add a catalyst

Enzyme

Biological catalyst

Iron catalyses

the Haber process