Question 3: Water flowing at the rate of 1.1 kg/s in a 2-4 shell-and-tube heat exchanger is heated from 50 °C to 90 °C by an oil having a heat capacity of 1.9 kJ/kg.K. The oil enters the heat exchanger at 125 °C and leaves at 90 °C. Calculate the area of the exchanger if the overall heat-transfer coefficient is 250 W/m².K. Question 4: A well stirred storage vessel is originally filled with 500 kg of 20 wt % ethanol solution. The operator decided to dilute the solution in the vessel by flowing a 10 wt % ethanol solution at a rate of 1000 kg/h into the vessel and withdrawing the well stirred solution from the vessel at a rate of 500 kg/h. (a) Calculate the time it takes the solution in the vessel to reach a concentration of 15 wt % ethanol. (b) If the vessel can only hold 1500 kg of the solution, calculate the ethanol concentration when the vessel is completely filled. Assume that the density of ethanol solution during the operation remains essentially constant within the ethanol concentration range of operation.

What is a residue-curve map?

Please answer question 3.

Diagrams need also for this. 2-Electrolyte: The intricate dance of electrons is aided by a liquid bridge filled with a redox mediator between the anode and counter electrode.