Changes in temperature,
concentration of solution, gas
pressure, surface area of solids
and the presence of catalysts all
affect the rates of reactions.
The rate of a chemical reaction can be found by measuring the
amount of a reactant used or the amount of product formed over time.
Chemical reactions can only occur when reacting particles collide
with each other and with sufficient energy. The minimum amount of
energy particles must have to react is called the activation energy.
Increasing the
temperature increases
the speed of the reacting
particles so that they
collide more frequently
and more energetically.
This increases the rate
of reaction.
Increasing the pressure of reacting gases
increases the frequency of collisions and so
increases the rate of reaction.
Increasing the concentration of reactants in solutions
increases the frequency of collisions and so increases the
rate of reaction.
Increasing the surface area of
solid reactants increases the
frequency of collisions and so
increases the rate of reaction.
Catalysts change the rate of
chemical reactions but are not used
up during the reaction. Different
reactions need different catalysts.
Catalysts are important in increasing the rates of chemical
reactions used in industrial processes to reduce costs.