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Rates of Chemical Reactions
Use this simulation to study the rate of chemical reactions.

The rate of chemical reactions is a function of reaction type and reagent concentrations. A parameter known as the reaction order is of considerable importance in this relationship. Reaction order is a value of power to which reagent concentration value should be raised in order to obtain the current reaction rate (the result of involution should be multiplied by the rate constant). The number of molecules of a given substance that is involved in one reaction determines the reaction order at low concentration of reagents.

This simulation represents the reactions of first and second order. Pay especial attention to the content vs. time graph. By starting up the process for several initial concentrations as a part of the same reaction, you will be able to observe all data points simultaneously.

Compare the properties of the curves that result from the first and the second order reactions. As you can see, in the first order reactions, the effect of the initial parameters on the reaction rate is quite strong (the bundle of curves is relatively wide at the end). In the second order reactions, the dependence of rate on the initial parameters is considerably less significant, since the concentration effect prevails. This leads to a rapid decrease in the distance between the curves of the different initial concentration values.

Note that the data points pertaining to different reactions of the same order are quite similar in their pattern, in spite of the considerably different rate constants. This happens because in this simulation, the scale of the plots is also a function of the rate constant.

In this simulation, reaction rate is displayed in a numerical form (in order to get more details on the current state of any reaction, press "Stop" button). The rate can also be seen as a slope of the curve at any point, taken with an opposite sign. The tangent to the curve is shown as a dotted line. Note that in the course of reaction, the slope decreases. The reaction rate decreases because of the decrease in reagent concentration.

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