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IB chemistry Designed Practical
Rate of Reactions:
Effect of Temperature on the Rate of Reaction of an Iodine Clock Reaction






















Theory: There are three factors which will affect the rate of a reaction which does not produce any gases and in which there are no solids. These are:
1. Changing the concentration of a reactant,
2. Changing the temperature at which a reaction occurs
3. Using a catalyst.
The basic theory of kinetics specifies that particles must collide in order to react. Not only must they collide, but they must collide with more than the activation energy of the reaction. Therefore, anything that increases either the frequency of particle collision or collision energy should increase the rate at which a reaction occurs.
Increasing the concentration of a reactant increases the number of particles of that reactant available to collide with other reactants. This increases the frequency of collisions and therefore should increase the reaction rate. It should be logical to assume that doubling the concentration of a reactant will double the number of collisions that reactant undergoes and should therefore double the rate of the reaction.
Increasing the temperature of a reaction supplies more energy to all of the reactants. Since temperature is a measure of kinetic energy this means that all of the reactant particles will be moving faster. This both increases the frequency of collisions and increases the energy of the collisions. This, of course, means that more collisions with energy greater than the activation energy will occur and that the rate will therefore increase.
The addition of a catalyst will increase the rate of a reaction but has no affect on the frequency or energy of the collisions....