Below is a simulation of a well-mixed reactor. The feed concentration of reactant A is fixed at 1 mol/m3. The reactor can be operated in a batch mode or in an open flow mode. When the outlet valve is open at the same time as one or both of the inlet valves, the outlet flow rate is set equal to the total inlet flow rate such that you can obtain steady-state CSTR operation. When the outlet valve is open when both inlet valves are closed, then the outlet flow rate is set to the maximum possible feed rate of reactant A solution. By pausing the reaction and/or the entire simulation, you can set up various initial conditions.