Algorithms which relate to the generation of positive compositional structures in chemical reaction systems are presented. The algorithms are applied to the following problems: (1) determine if a specified reaction system is proper; (2) given a reaction system, determine a minimum initial mix which allows all reactions to proceed, or conversely given an initial mix, determine the number of free reactions; (3) given a reaction system and a consistent set of reactant molecular weights, determine a proper moiety structure for the reactants; (4) given a steady-state network and a consistent set of one-way reaction rates, determine a proper reaction path structure for the network.