Points to the direction of the chemkin-file.
This file contains the information of which species that will be used in the calculation and what chemical reactions will be used for the chemistry. It typically looks like this:
ELEMENTS H O C N END SPECIE C7H16 O2 N2 CO2 H2O END REACTIONS C7H16 + 11O2 => 7CO2 + 8H2O 5.00E+8 0.0 15780.0 FORD / C7H16 0.25 / FORD / O2 1.5 / END
For the above setting the reaction rate will be
where is the molar concentration.
For more information I recommend http://www.galcit.caltech.edu/EDL/public/formats/chemkin.html