Rates of reaction

There are 4 main factors which affect the rate of a reaction; they are:

• temperature
• pressure (gases)
• catalyst
• surface area (SA)

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

ACTIVATION ENERGY = the minimum amount of energy needed to start a reaction

TEMPERATURE

• as the temperature increases, the rate of reaction increases
• the time taken for the reaction will decrease

EXPLANATION:

• as the temperature increases the rate of reaction also increases
• because particles have greater kinetic energy
• therefore more successful frequent collisions
• energy is nearer the activation energy

CONCENTRATION

• as the concentration increases, the rate of reaction also increases

EXPLANATION:

• as concentration increases the rate of reaction increases
• because more particles in a given volume
• more frequent successful collisions

SURFACE AREA (SA)

• increased surface area, rate of reaction increases
• time taken will decrease
• smaller particles = larger SA

EXPLANATION:

• as the surface area increases, the rate of reaction increases
• greater number of surface area is exposed
• more frequent successful collisions

CATALYST

A catalyst is something that speeds up the rate of a reaction without being used up

• increase the mass of a catalyst, rate of reaction will increase

EXPLANATION:

• catalysts provide an alternative pathway that has a lower activation energy