What you’ll learn13 learning objectivesChoose one objective for a focused lesson, or study the complete topic.2.2.1Rate of reaction• Change in concentration per unit time• Determine rates from tangents of concentration, volume, or mass graphsSyllabus objective2.2.2Collision theory• Sufficient energy + proper orientation required• Kinetic energy and temperature (Kelvin)• Explain successful collisions using activation energy and orientationSyllabus objective2.2.3Factors affecting rate• Pressure, concentration, surface area, temperature, catalyst• Predict and explain rate changes when conditions changeSyllabus objective2.2.4Activation energy (Ea)• Minimum energy for successful collision• Maxwell-Boltzmann distribution curves• Use Maxwell-Boltzmann curves to show temperature effects on successful collisionsSyllabus objective2.2.5Catalysts• Provide alternative pathway with lower Ea• Energy profiles with/without catalysts• Explain catalyst effects on energy profiles and Maxwell-Boltzmann distributionsSyllabus objective2.2.6(HL)—Reaction mechanisms• Series of elementary steps• Slowest step = rate-determining• Intermediates vs. transition states• Evaluate proposed mechanisms against kinetic and stoichiometric dataSyllabus objective2.2.7(HL)—Energy profiles• Show Ea and transition state of rate-determining step• Construct and interpret multistep energy profiles from kinetic dataSyllabus objective2.2.8(HL)—Molecularity• Number of particles in elementary step• Unimolecular, bimolecular, termolecularSyllabus objective2.2.9(HL)—Rate equations• Determined experimentally, depend on mechanism• Deduce rate equations from experimental dataSyllabus objective2.2.10(HL)—Reaction order• Exponent in rate equation• Zero, first, second order• Overall order = sum of individual orders• Analyse concentration-time and rate-concentration graphsSyllabus objective2.2.11(HL)—Rate constant (k)• Temperature dependent• Units from overall order• Solve rate equation problems, including units of kSyllabus objective2.2.12(HL)—Arrhenius equation• Temperature dependence of k determines Ea• Linear form: ln k vs. 1/TSyllabus objective2.2.13(HL)—Arrhenius factor (A)• Frequency of proper collision orientations• Determine activation energy and Arrhenius factor from dataSyllabus objective