Initial rate equations conformation change

In general, it is not strictly correct to conclude that a particular reaction order fits the data based simply on the conformity of data to an integrated equation. As illustrated above, multiple initial concentrations which vary considerably should be employed to assess whether the rate is independent of concentration. Multiple integrated equations should also be tested. It may be useful to show that the reaction rate is not affected by species whose concentrations do not change considerably during an experiment these may be substances not consumed in the reaction (i.e., catalysts) or present in large excess [23,108]. 

The methods of approximation are mathematically very useful nevertheless, the analysis of complex processes is labor intensive. In addition, the quality of the approximation can usually not be indicated. Therefore, in the age of electronic data processing it is more reliable, easier and more convenient to calculate the temporal course of both the concentrations and the thermal reaction power by means of computers. For this purpose we elaborate on the basis of both a presumed mechanism of the reaction and the relevant rate functions the relations for the rate of change in the concentration of each reactant, of each intermediate product and of each product as well as the corresponding functions of the thermal reaction power using (4.1), (4.3), (4.4), (4.7) and (4.9). The obtained system of equations is solved by numeric calculation. For this we need, in addition to the mathematical relations and their initial values, the orders of rates, the rate coefficients and the enthalpies of reactions (if necessary, estimated first). We obtain the temporal course of the concentrations of the participating species, the temporal course of the thermal reaction power of each stage and the temporal course of its superposition, i.e. the measurable thermal reaction power. The calculated results are compared with the measured quantities. In case of a deviation, the parameters of the rates and enthalpies as well as, if necessary, the reaction model itself are varied many times until the numeric and experimental results sufficiently correspond. Any further conformance between a new experiment and its calculation confirms the elaborated reaction kinetics, but it is not a mathematically definitive demonstration, such as the proof from to + 1. 

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