International Baccalaureate IB Chemistry

The rate of reaction is expressed as the change in concentration of a particular reactant/product per unit time.

Determine rates of reaction.

Species react as a result of collisions of sufficient energy and proper orientation.

Explain the relationship between the kinetic energy of the particles and the temperature in kelvin, and the role of collision geometry.

Factors that influence the rate of a reaction include pressure, concentration, surface area, temperature and the presence of a catalyst.

Predict and explain the effects of changing conditions on the rate of a reaction.

Activation energy, $E_a$, is the minimum energy that colliding particles need for a successful collision leading to a reaction.

Construct Maxwell–Boltzmann energy distribution curves to explain the effect of temperature on the probability of successful collisions.

Catalysts increase the rate of reaction by providing an alternative reaction pathway with lower $E_a$.

Sketch and explain energy profiles with and without catalysts for endothermic and exothermic reactions.

Energy profiles can be used to show the activation energy and transition state of the rate‑determining step in a multistep reaction.

Construct and interpret energy profiles from kinetic data.

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

Interpret the terms “unimolecular”, “bimolecular” and “termolecular”.

Rate equations depend on the mechanism of the reaction and can only be determined experimentally.

Deduce the rate equation for a reaction from experimental data.

The order of a reaction with respect to a reactant is the exponent to which the concentration of the reactant is raised in the rate equation.

The overall reaction order is the sum of the orders with respect to each reactant. 

Sketch, identify and analyse graphical representations of zero, first and second order reactions.

The Arrhenius equation uses the temperature dependence of the rate constant to determine the activation energy.

Describe the qualitative relationship between temperature and the rate constant. 

Analyse graphical representations of the Arrhenius equation, including its linear form.

The Arrhenius factor, A, takes into account the frequency of collisions with proper orientations.

Determine the activation energy and the Arrhenius factor from experimental data.