Chapter 13 Outline


This chapter is about kinetics, the rates of chemical reactions. This chapter introduces how long it takes for a reaction to occur. The mathematics for this chapter is siginficantly more complex than we have used up to this point. If logarithms or graphs are rusty you should review these. If you have taken calculus you will find this chapter very familiar. We will use integration and derivitives to solve chemical problems. If you have not had calculus, don't worry, you will be given the equations that you need. If you have had calculus, you should be able to derive all the equations in this chapter. The ideas presented in this chapter are complex and interconnected. If you study hard and work carefully the pieces will all fit together very nicely. If you look at the pieces as separate, you will probably be overwhealmed. If you are lost or confused, get help early.

13.1 Catching Lizards


13.2 The Rate of a Chemical Reaction

This section introduces the basic concept that chemical reactions do not occur instantaneously. A detail that we had ignored up to this time. The most basic concept is the rate of a reaction, how fast is it going. The rate of a reaction is given as a change with time (just like the rate of your care is give as distance with time). Typically rate = (change in concentration)/(change in time). So if you have a graph of concentration (y-axis) vs time (x-axis) the slope is the rate. For some reactions the rate is constant, for other reactions the rate changes. The details we will get to latter in the chapter.

13.3 The Rate Law: The Effect of Concentration on Reaction Rate

For almost all reactions the rate of the reaction depends upon the concentration of the reactants. In general for a reaction where:
aA + bB -> cC + dD
rate = k [A]x [B]y
Where k is the rate constant. Most of this section is about determining the vraiables in the rate equation (rate, k, x, and y).

13.4 The Integrated Rate Law: The Dependence of Concentration on Time

This section is about determinging the concentration at different times. By taking the rate equation and integrating it you can find the concentration of the reactants and products at any time. You need to be able to use the integrated rate equation for different reaction orders. Notice that there is a different form of the integrated rate equation for differnent reaction orders. This section also shows how these equations are used with graphs. Pay close attention to these graphs, understanding them will help you understand the equations.

13.5 The Effect of Temperature on Reaction Rate

This section covers the major experimental conditions that change the rate of a reaction. These are the concentration, the temperature, and the use of a catalyst. These are each delt with in detail latter in the section.

13.6 Reaction Mechanisms

Understanding the kinetics of a reaction makes it possible to idenify the reaction mechanism. The sequence of fundamental steps required for the reaction to occur. This gives understanding of chemical reactions at the most fundamental level.

13.7 Catalysis


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Scott Van Bramer
Department of Chemistry
Widener University
Chester, PA 19013

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Last Updated Friday, May 25, 2001 2:11:17 PM