Stoichiometric Coeff statements
 

I'm new to UDF, so I'm sorry if this is an easy/stupid question:

In the Fluent UDF manual, i find many examples including statements for finite-rate reactions, such as: r->name, r->reactant[], r->A, r->E, r->b, r->n_reactants, but in that manual they just "use" those statements but there is not a list of tha available statements.

I need to model C oxidation reaction aC + bO2 --> cCO + dCO2, where the stoichiometric coefficients are temperature dependent, I would like to define those coeffs with an UDF but I don't know how they are identified.

thanks for your help