Stoichiometry and Kinetics of Chemical Reactions

A homogeneous system can be locally characterized by the velocity, the concentrations of all the chemical species, and one thermodynamic variable, such as the temperature or the internal energy. These variables will be called the state variables. A nonuniform or distributed system is completely specified by the values of the state variables at each point of the system, while a uniform system, not having any space variations, is specified by the values of the state variables at a single point. 

The evolution of systems with chemical change is described by the equations of conservation of momentum, energy, and mass of each chemical species. The conservation equations for the chemical species contain source terms due to the chemical reactions. Certain linear combinations of these source terms vanish due to the conservation of atomic species in each chemical reaction. This property has very important implications for the mathematical structure of the differential equations describing uniform and distributed reacting systems. 

Let us consider a homogeneous mixture of N chemical species denoted by the symbols These species consist of a number 

By convention, the species is called a reactant or a product of the reaction according to whether Vj 0 or v, 0. 

The reaction system (1.1.3) is capable of describing the chemical change if with each reaction we can associate a function fj of the N -h 1 state variables (e.g. the N concentrations and the temperature) such that  

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