Absorbance and degree of advancement

The change in absorbances during a chemical reaction can be calculated via the balanced equations as has been demonstrated in the proceeding ex- 

The vector x consists of exactly s elements. The vector E is represented by h elements, h can be any number. Under these conditions the matrix Q consists of h rows and s columns. The special case s = /t is very essential. If the wavelengths A had been chosen such that Q is regular, a reciprocal matrix exists and using eq. (5.58) one obtains 

Under these conditions one can determine the linear independent degrees of advancement by use of absorbance measurements if the elements of Q are known. 

Example 5.19 Transformation concentration to absorbance for a consecutive photoreaction For the reaction 

They are the stoichiometric sums of the elements eJ. and can be directly taken out of the general scheme explained in Section 2.1.1.1. For this reason one multiplies the stoichiometric coefficients in the i(th row with the absorption coefflcients of those reactants in the related columns. 

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