All the concentrations at one reaction time are known

If the composition of the solution is known at any time, t as well as the concentration of the starting material and that of the final products, one can 

Survey on possible reaction with two linear independent steps 

In the case where a, 0, one lengthens AV up to point I in such a way that the sections 1 to I A have the same ratio as a. to a . In this case point 1 is situated on BC. Next the point I A is looked for, which intersects this section with the ratio a = a t) / a . Once more the parallel to the interconnection line passing point 1 drawn. The side BC is found on this straight line. Under these conditions one of the reactions 4, 9 or 10 takes place. 

The direction AB is determined in the same way by intersecting AV with the ratio y = c(t) / c . This point is connected with P. The comer P is situated on the parallel passing A. It forms the intersection point with the paral-lels passing the points V or 1 . By these means the length of the section AB becomes known. If it is intersected with the ratio p = b t) / a , one finds the connection line to point B in the direction of i4C. The parallel passing A intersects the straight line passing B and 1 or in point C. By these methods all concentrations are found as functions of time. 

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