What factors affect the rate of a reaction?

i) Concentration of reactants, or pressure for gases-  As there are more particles in a certain volume, they collide more often so there is a greater chance of successful collisions per unit timeii) Pressure (when gases are involved)iii) Surface area (of solid reactants)- The number of particles exposed increases, thus increasing the effective concentration of the reactant, again leading to a greater chance of successful collisionsiv) Temperature - An increase in temperature increases the average number of collisions per unit time, but also increases the kinetic energy of the particles. Thus, there is a greater chance of collisions but as the particles collide harder there is also a larger proportion of particles with greater energy than the activation energy, so more collisions are successful as well.v) Catalysts- Allow the reaction to proceed via an alternative pathway of lower activation energy, increasing the rate