Q2a: In a process unit, a component with the concentration of Cin (6) enters at constant flow rate into a holding tank with a constant volume and then discharges to a river at the concentration of C(t). Assuming a perfectly mixed tank, set up an unsteady state mass balance for the concentration of C(t) in the tank. If a change in the upstream process causes a step change of 0.5u(t) in the concentration, apply the Laplace transform method to find concentration as a function of time, Ct). 11