KineticsLectureNotes - 1 Reaction Kinetics Dr Claire...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Reaction Kinetics Dr Claire Vallance First year, Hilary term Suggested Reading Physical Chemistry , P. W. Atkins Reaction Kinetics , M. J. Pilling and P. W. Seakins Chemical Kinetics , K. J. Laidler Modern Liquid Phase Kinetics , B. G. Cox Course synopsis 1. Introduction 2. Rate of reaction 3. Rate laws 4. The units of the rate constant 5. Integrated rate laws 6. Half lives 7. Determining the rate law from experimental data (i) Isolation method (ii) Differential methods (iii) Integral methods (iv) Half lives 8. Experimental techniques (i) Techniques for mixing the reactants and initiating reaction (ii) Techniques for monitoring concentrations as a function of time (iii) Temperature control and measurement 9. Complex reactions 10. Consecutive reactions 11. Pre-equilibria 12. The steady state approximation 13. ‘Unimolecular’ reactions – the Lindemann-Hinshelwood mechanism 14. Third order reactions 15. Enzyme reactions – the Michaelis-Menten mechanism 16. Chain reactions 17. Linear chain reactions The hydrogen – bromine reaction The hydrogen – chlorine reaction The hydrogen-iodine reaction Comparison of the hydrogen-halogen reactions 18. Explosions and branched chain reactions The hydrogen – oxygen reaction 19. Temperature dependence of reaction rates The Arrhenius equation and activation energies Overall activation energies for complex reactions Catalysis 20. Simple collision theory
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 1. Introduction Chemical reaction kinetics deals with the rates of chemical processes. Any chemical process may be broken down into a sequence of one or more single-step processes known either as elementary processes , elementary reactions , or elementary steps . Elementary reactions usually involve either a single reactive collision between two molecules, which we refer to as a a bimolecular step, or dissociation/isomerisation of a single reactant molecule, which we refer to as a unimolecular step. Very rarely, under conditions of extremely high pressure, a termolecular step may occur, which involves simultaneous collision of three reactant molecules. An important point to recognise is that many reactions that are written as a single reaction equation in actual fact consist of a series of elementary steps. This will become extremely important as we learn more about the theory of chemical reaction rates. As a general rule, elementary processes involve a transition between two atomic or molecular states separated by a potential barrier. The potential barrier constitutes the activation energy of the process, and determines the rate at which it occurs. When the barrier is low, the thermal energy of the reactants will generally be high enough to surmount the barrier and move over to products, and the reaction will be fast. However, when the barrier is high, only a few reactants will have sufficient energy, and the reaction will be much slower. The presence of a potential barrier to reaction is also the source of the temperature dependence of reaction rates, which we will cover in
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 31

KineticsLectureNotes - 1 Reaction Kinetics Dr Claire...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online