AbstractPart 2, of two articles, outlines a finite‐difference computing scheme for the reactor model of Part 1, based on implicit backward differences for linear terms and explicit evaluation of non‐linear terms. The chemical system,vAA→B→vCC, withBthe desired product, is examined through case studies to find sources of chemical yield loss. The system is gas phase, with exothermic reactions and Arrhenius temperature activation.Under moderate reaction conditions: 1. Activation energy differences cause yield losses of 4–8%. 2. Radial mixing causes yield losses up to 6%. 3. Failure to withdraw the stream where local yields are maximum causes yield losses larger than 1%.A technique for reactor design by simulation is