Reaction speeds and concentrations

During the stndy of numerous reactions occnrring in solution, the measurement of concentrations is frequently used. 

Concentration in a reaction zone is defined as the amount of substance contained in the unit volume of this area. In the case of homogeneous and nniform reactions, a component will only have one concentration  

In the case of 2D zones, the concept of superficial concentration is sometimes used, which is the amount of substance contained on a unit area of a surface. 

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The relationships between reaction speed and concentrations of reactants, products or catalysts are extremely complex and varied. We will see that the diversity of these relations is a real treasure and makes speed-concentration relationships at constant temperature the main tool of justification for a mechanism. 

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