Kinetics and Reaction Dynamics

50 lessons, pages 3101–3150.

  1. From Rate Laws to Reaction Dynamics — Why molecular-level theories are needed to explain measured rate constants
  2. Differential and Integrated Rate Laws Revisited — Solving rate equations and linking them to mechanisms at university level
  3. Complex Rate Laws and Numerical Integration — Coupled rate equations, fractional orders and computer solutions
  4. Relaxation Methods for Fast Reactions — Temperature-jump perturbations and relaxation times near equilibrium
  5. Stopped-Flow and Flash Photolysis Techniques — Measuring millisecond to femtosecond reactions
  6. Kinetic Theory Foundations for Rate Theory — Maxwell-Boltzmann speed distributions and mean relative speed
  7. Collision Frequency and Collision Cross-Section — Hard-sphere model, reduced mass and collision density
  8. The Simple Collision Theory Rate Constant — Combining collision density with the Boltzmann energy factor
  9. The Steric Factor — Orientation requirements and the gap between theory and experiment
  10. Reactive Cross-Sections and Collision Energy — Energy-dependent cross-sections, line-of-centres model and the harpoon mechanism
  11. Strengths and Limits of Collision Theory — Where hard-sphere pictures succeed and where they fail
  12. Potential Energy Surfaces — Mapping energy as a function of nuclear positions for a reacting system
  13. Saddle Points and the Minimum-Energy Path — Locating the transition state and defining the reaction coordinate
  14. Trajectories and Energy Disposal — Early and late barriers, Polanyi rules and product energy distribution
  15. Molecular Beam Experiments — Crossed beams, state-resolved products and angular scattering
  16. Transition-State Theory: Core Assumptions — Quasi-equilibrium, no recrossing and separable reaction coordinate
  17. The Activated Complex and Its Equilibrium Constant — Treating the transition state as a species in quasi-equilibrium with reactants
  18. The Eyring Equation — Deriving k = (kBT/h)K‡ and the universal frequency factor
  19. Enthalpy and Entropy of Activation — Thermodynamic formulation of transition-state theory and Gibbs energy of activation
  20. Eyring Plots and Activation Parameters — Extracting activation enthalpy and entropy from temperature data
  21. Comparing Arrhenius, Collision and Eyring Parameters — Relating Ea, A, steric factor, activation enthalpy and activation entropy
  22. Transmission Coefficients and Quantum Tunnelling — Recrossing, tunnelling corrections and curved Arrhenius plots
  23. Kinetic Isotope Effects — Zero-point energy differences and primary and secondary isotope effects
  24. The Lindemann-Hinshelwood Mechanism — Collisional activation and pressure dependence of unimolecular reactions
  25. RRK and RRKM Theory in Outline — Energy randomisation among vibrational modes and fall-off curves
  26. Termolecular and Pressure-Dependent Reactions — Third-body recombination and negative apparent activation energies
  27. Chain Reaction Kinetics — Initiation, propagation, termination and chain length
  28. The Hydrogen-Bromine Chain Reaction — Deriving a complex rate law with the steady-state approximation
  29. Branching Chains and Explosion Limits — Why chain branching leads to runaway rates, treated conceptually
  30. Diffusion-Controlled Reactions in Solution — Encounter pairs, Smoluchowski limit and viscosity dependence
  31. Activation Control and the Cage Effect — Solvent cages, encounter lifetimes and the diffusion-activation balance
  32. Ionic Strength and the Kinetic Salt Effect — Transition-state theory with activity coefficients and the Brønsted-Bjerrum equation
  33. Electron Transfer and Marcus Theory — Reorganisation energy, parabolic free-energy surfaces and the inverted region
  34. The Hammond Postulate and Free-Energy Relationships — Early and late transition states and linear free-energy correlations
  35. Kinetics of Surface-Catalysed Reactions — Langmuir-Hinshelwood and Eley-Rideal mechanisms
  36. Enzymes as Biological Catalysts — Active sites, specificity and the kinetic signature of saturation
  37. The Michaelis-Menten Mechanism — Enzyme-substrate complex formation and product release
  38. Deriving the Michaelis-Menten Equation — Steady-state treatment and enzyme conservation
  39. Interpreting Km, Vmax and kcat — Meaning of each parameter and the turnover number
  40. Catalytic Efficiency and Catalytic Perfection — The specificity constant kcat/Km and the diffusion ceiling
  41. Linearised Enzyme Kinetic Plots — Lineweaver-Burk, Eadie-Hofstee and Hanes-Woolf plots and their error weighting
  42. Competitive Inhibition — Inhibitors competing for the active site and apparent Km
  43. Uncompetitive and Mixed Inhibition — Binding to the enzyme-substrate complex and diagnostic plot patterns
  44. Irreversible Inhibition and Enzyme Inactivation — Covalent modification, time-dependent loss of activity and suicide substrates
  45. Temperature and pH Effects on Enzyme Rates — Activation versus denaturation and ionisable active-site groups
  46. Multisubstrate Enzyme Kinetics — Sequential and ping-pong mechanisms
  47. Allosteric Enzymes and Cooperativity — Sigmoidal kinetics, the Hill equation and regulation
  48. Transition-State Stabilisation in Enzyme Catalysis — Linking transition-state theory to enzyme rate enhancement and transition-state analogues
  49. Reaction Dynamics Problem-Solving Workshop — Multi-step problems combining collision theory, Eyring analysis and enzyme kinetics
  50. Kinetics and Reaction Dynamics: Unit Review — Connecting molecular dynamics, rate theories and enzyme kinetics