IB Chemistry Unit 6: Kinetics

IB CHEMISTRY Unit 6: KINETICS
STANDARD LEVEL: Number Objective Rates of Reaction Define the term rate of reaction. Describe suitable experimental procedures for measuring rates of reactions. Analyze data from rate experiments. Students should be familiar with graphs of changes in concentration, volume and mass against time. Collision Theory Describe the kinetic theory in terms of the movement of particles whose average energy is proportional to the temperature in Kelvins. Define the term activation energy (Ea). Describe the collision theory. Students should know that reaction rate depends on:  Collision frequency  Number of particles with E > Ea  Appropriate collision geometry or orientation Predict and explain, using collision theory, the qualitative effect of particle size, temperature, concentration and catalysts on the rate of a reaction. State and explain qualitatively the Maxwell-Boltzmann energy distribution curve for a fixed amount of gas at different temperatures and its consequence for changes in the reaction rate. Students should be able to explain why the area under the curve is constant and does not change with temperature. Describe the effect of a catalyst on a chemical reaction. Sketch and explain Maxwell-Boltzmann curves for reactions with and without catalysts.

6.1.1 6.1.2 6.1.3

6.2.1 6.2.2 6.2.3

6.2.4 6.2.5

6.2.6 6.2.7

Higher Level Number Objective
Rate Expressions

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Distinguish between the terms rate constant, overall order of reaction, and order of reaction. Deduce the rate expression for a reaction from experimental data. Solve problems involving the rate expression. Sketch, identify and analyze graphical representations for zero, first and second order reactions. Students should be familiar with both concentration-time and rate-concentration graphs.

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Reaction Mechanism Explain that reactions can occur in more than one step and that the slowest step determines the rate of the reactions (rate determining step). Describe the relationship between reaction mechanism, order of reaction and ratedetermining step. Only examples to one- or two-step reactions where the mechanism is given will be assessed. Activation Energy Describe qualitatively the relationship between the rate constant (k) and temperature (T). Determine activation energy values from the Arrhenius equation by a graphical method. The Arrhenius equation: data booklet. and its logarithmic form are provided in the chemistry

16.3.1 16.3.2