P5-15 OEQ (Old Exam Question). The gaseous reaction AB has a unimolecular reaction rate constant of 0.0015min1 at 80F. This reaction is to be carried out in parallel tubes 10ft long and 1in. inside diameter, under a pressure of 132 psig at 260F. A production rate of 1000lb/h of B is required. Assuming an activation energy of 25000cal/mol, how many tubes are needed if the conversion of A is to be 90% ? Assume perfect gas laws. A and B each have molecular weights of 58 . Source: From California Professional Engineers' Exam