The Demonstration plots the conversion versus reactor volume for either a CSTR (continuous stirred-tank reactor) or a PFTR (plug flow tubular reactor). The volume (in liters) required to obtain 90% conversion in the reaction is indicated by the green dot in the figure. The reaction takes place in the gas phase with a rate constant . The feed flow rate is and corresponds to a composition such that This is a high-pressure gas-phase reaction since . You can set the value of . Based on the present calculation, you can draw the following conclusions: (1) to achieve the desired conversion, the required reactor volume is larger for the CSTR than the PFTR; and (2) if the reaction reduces the number of moles (e.g., , the required reactor volume is smaller. For example, if , the reaction produces more moles, thus diluting the reactant and causing the volume to be larger.