Relationship between concentration and fractional extent in a closed environment

Relationship between concentration and fractional extent in a closed environment 

If the zone is closed with respect to component the only cause of variation in concentration over time is the reaction and, therefore, by using equations [1.15] and [1.29] and by assigning the index zero to the magnitude values at the start of a reaction, we get  

In the case of gaseous components, assuming an ideal gas, the concentration can be replaced by the partial pressure by using  

If several reactions involving the same constituent k, whose stoichiometric coefficient in the p-th reaction is v p occur in the same zone, then equation [1.30] 

Expression of volumetric speed according to variations in concentration in a closed system 

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