• Reactions may occur by more than one step and the slowest step determines the rate of reaction (rate determining step/RDS).

• The molecularity of an elementary step is the number of reactant particles taking part in that step.

• The order of a reaction can be either integer or fractional in nature. The order of a reaction can describe, with respect to a reactant, the number of particles taking part in the rate- determining step.

• Rate equations can only be determined experimentally.

• The value of the rate constant (k) is affected by temperature and its units are determined from the overall order of the reaction.

• Catalysts alter a reaction mechanism, introducing a step with lower activation energy.

• Deduction of the rate expression for an equation from experimental data and solving problems involving the rate expression.

• Sketching, identifying, and analysing graphical representations for zero, first and second order reactions.

• Evaluation of proposed reaction mechanisms to be consistent with kinetic and stoichiometric data.

• Calculations will be limited to orders with whole number values.

• Consider concentration against time and rate against concentration graphs.

• Use potential energy level profiles to illustrate multi-step reactions; showing the higher Ea in the rate-determining step in the profile.

• Catalysts are involved in the rate-determining step.

• Reactions where the rate-determining step is not the first step should be

considered.

• Any experiment which allows students to vary concentrations to see the effect upon the rate and hence determine a rate equation is appropriate.