Abstract: In the framework of stochastic theory of chemical reactions, we examined the master equation for the chemical Lorenz system. Directd simulatation studies show that in the chaotic regime the mass action kinetics at the macroscopic level no longer provide a correct collective description of the underlying reaction processes. These results indicate that a microscopic or at least mesoscopic description is necessary in this circumstance.

Key words: Chemical Lorenz system, Molecular fluctuation, Stochastic simulation, Chemical chaos