Kinetics and Chemical Reaction Stoichiometry

All chemical change is subject to the law of conservation of mass, including the conservation of the chemical elements making up the species involved, which is called chemical stoichiometry (from Greek relating to measurement (-metry) of an element (stoichion)). For each element in a closed reacting system, there is a conservation equa- 

Alternatively, the conservation of atomic species is commonly expressed in the form of chemical equations, corresponding to chemical reactions. We refer to the stoichiometric constraints expressed this way as chemical reaction stoichiometry. A simple system is represented by one chemical equation, and a complex system by a set of chemical equations. Determining the number and a proper set of chemical equations for a specified list of species (reactants and products) is the role of chemical reaction stoichiometry. 

The oxidation of sulfur dioxide to sulfur trioxide in the manufacture of sulfuric acid is 

Equation (A) or (B) stems from the fact that the two element balances involve three quantities related to amounts of the species. These balances may be written as follows  

The entries in A are the subscripts to the elements in the molecular formulas of the substances (in an arbitrary order). Each column is a vector of the subscripts for a substance, and A is called a formula matrix. 

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