When modeling a packed bed reactor, we include pressure drop and the energy balance in addition to a mole balance modified for mass transfer, catalyst decay, and residence time distribution, along with all supporting auxiliary equations, because (choose all that apply): making the steady state assumption requires we use all of these equatons. reactions reach equilibirum sorption is always the limiting step in packed beds, and all of these equations are needed to describe it. experience with real reactors showed that all of these phenomena needed to be accounted for extent of reaction is negative we need to figure out which of these factors is limiting the reaction so we can design a better reactor or find better conditions complicating things is what professors do many of these phenomena make conversion go down, so to properly size a reactor we need to model all the nonidealities when considering mass and energy in a volume, these considerations naturally arise