Derive a model for an ideal isothermal plug flow reactor (pfr) in which the reaction 2a + b takes place. let the forward rate constant be k, and the reverse rate constant k2 (both based on a), the reactor cross sectional area be ac, the velocity v ef/a), and the feed concentration caf. initially the rector contains no a. make sure that your model is complete, i. e. it provides all information needed to solve it. classify your model (e. g., linear ordinary differential equations). how do your model equations change if you also assume steady state?