2_Kinetics_chap10

2_Kinetics_chap10 - Chemical Kinetics (reaction rates) Chem...

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Chemical Kinetics (reaction rates) Chem 300
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The difference between a reaction rate and a rate constant. Rate laws for Frst, psuedo-Frst and second order reactions. How to determine a reaction rate from a graph and from data. How to classify the order of a reaction. Half-lives and time constants Kinetics concepts to review on your own
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What we’ll cover in Chapters 10 and 11 Kinetic theories Arrhenius theory (10. Collision theory (10. Transition state theory (10. Rate control (11. The steady-state approximation (11. Enzymes as catalysts (11. Relaxation methods (11.
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Why do we need kinetics? The following reactions are spontaneous in the direction written: Diamond Graphite ATP ADP + Pi Oxidation of glucose Virtually all metabolic reactions are slow on a physiological time scale, regardless of whether they occur spontaneously or not. Enzymes are the catalysts needed to speed up the reaction Studying the rates of the reactions let us to predict how quickly the reaction mixture approaches equilibrium
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How do we measure kinetics? The method chosen depends on the time-scale of the process and what physical properties of the reactant and/or product can be detected. UV-Vis spectrophotometry is one of the most widely used methods of detection.
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Methods for measuring fast reaction rates Stopped Fow (ms-s): Reagents are mixed very rapidly and monitored in an observation cell. Timescale is controlled by stopping syringe. ±lash photolysis (fs-ns): ±lash of light initiates reaction. Quenching (s-min): Reaction is stopped (quenched) typically by freezing. Useful for detecting short lived intermediates.
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mol L 1 s 1 ( ) υ = Rate = d [ J ] dt The rate of chemical reaction: Method of initial rates Because the rate of a reaction changes as reactant is consumed and product builds up, the initial rate must be measured.
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A + B C Rate law is established experimentally and can not in general be inferred from the chemical equation for the reaction What’s the difference between a rate and a rate constant? (Rate law) Changing the concentration of a reactant changes the reaction rate (v) of the reaction. A rate constant (k) is unaffected by changes in concentrations of reactants and products and is multiplied by the concentration of reactant(s) to obtain a reaction rate.
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This note was uploaded on 12/04/2011 for the course CHEM 300 taught by Professor N.gerber during the Fall '11 term at S.F. State.

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2_Kinetics_chap10 - Chemical Kinetics (reaction rates) Chem...

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