Reaction too slow to occur within the diffusion film

7 Reaction too slow to occur within the diffusion film 

For reactions with a first-order (or pseudo-first-order) rate constant of 0.01s 1, little reaction will occur in the diffusion film. 

Such a system is included in Fig. 5.2 and is treated as a pseudo-equilibrium in which the chemical reaction rate at anytime during the reaction must be equal to the mass transfer rate. It is necessary to be careful in the choice of units. The chemical rate, r (in mol cm-3 s 1), can be written as Equation 5.2  

Following simplification of the expression obtained by substitution for Cbuik in Equation 5.3 using Equation 5.2, we obtain Equation 5.4  

Interfacial area per unit volume of receiving phase/cm 1 

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