4.20 Explain the effects of changes in surface area of a solid, concentration of solutions, pressure of gases and temperature on the rate of a reaction in terms of particle collision theory

Surface area
There is more surface that is in contact, so it's more likely that there will be successful collisions that lead to a reaction >> faster rate of reaction

Concentration/Pressure
There's more particles so, again, it's more likely that there will be successful collisions that lead to a reaction >> faster rate of reaction

Temperature
Particles are moving faster, so they collide more frequently. Because of this, there is going to be more successful collisions, which increases the rate of reaction

Catalysts
Catalysts make the reaction require less activation energy, providing an alternate "route" for the reaction