please explain every step and give a reason why the step is required

12. Heat exchanger design (10 points) A heat exchanger is to be constructed by forming copper tubing into a coil and placing the latter inside an insulated steel shell. In this exchanger, water will flow inside the tubing, and a hydrocarbon vapor at a rate of 0.126 kg/s will be condensing on the outside surface of the tubing. The inside and outside diameters of the tube are 0.0127 and 0.0152 m, respectively. Inlet and exit temperatures for the water are 10 and 32C, respectively. The heat of condensation of the hydrocarbon at a condensing temperature of 88C is 335 kJ/kg, and the heat transfer coefficient for the condensing vapor is 1420 W/m2.K. Heat losses from the shell may be neglected. What length of copper tubing will be required to accomplish the desired heat transfer? Data: Water: Cp=4151 J/kg:K, density = 997 kg/m3, viscosity = 9.94*10* Pas, k=0.61 W/mK; Copper: k = 385 W/mK