week 6

• The rate of a reaction is the change in the concentration of product formed per unit of time, or the change in the concentration of reactant used per unit of time
• rate = k × [reactant]n
• if the rate constant is larger, the reaction is faster
• reactions tend to occur in an open system which means the continuous mixing of reactants
• this means reactions occur in multiple steps and the slowest of these steps is the rate determining step
• many reactions in nature approximate to a first order reaction
• half life is the time taken for concentration to decrease to half it's initial value
• in first order reactions the half life is constant
• can use equation 1/2 life = ln/k only for first order reactions
• half life is not effected by the initial concentration of a reactant
• collision theory - particles must collide with enough energy for a reaction to occur
• activation energy is the minimum amount of energy required for a reaction to occur
• conc of reactants, temp, presence of organic coatings, biology (catalysts lower the activation energy), impurities (impurities act to increase the SA so there's more chance of a collision).all affect the rate of reaction