2.2.3 factors affecting rates of reactions

what 5 things affect the rate of reaction

concentration

pressure

temperature

surface area

catalyst use

why does an increased concentration lead to increased rate of reaction

increased concentration menas greater number of reactant particles and increased collision frequency so frequency of successful collisions increases, leading to increased rate of reaction

what is the relationship between pressure and rate of reaction

increase pressure leads to increased rate of reaction

why

when pressure increased, particles are compressed and have less space to move so collision frequency increases so number of successful collsions also increases

what is an increase in pressure the same as

increase in concentration

what happens to ror as temperature increases

increase temp leads to increased ror

why

at higher temperatures particles have more ek so are moving faster so collide more frequenly and total higher number of successful collisions and at higher temperature a higher proportion of particles have activation energy or more so higher proportion of successful collisons

what is the relationship between sa and ror

inverse relationship. decrease in sa leads to increased rate of reaction

why

if sa increased, more particles will be on surface and able to collide with paticles of other reactants so more collisions and more successful collisions

what does a catalyst provicde

a catalyst provides the reactants with an alternatuve reaction pathyway which is lower in activation energy that uncatalysed reaction so more collisions successful and rate of reaction increases

what happens to a cataylst in a reaction

undergoes no chemical change