1. (5 marks) An electric heating element is immersed in a tank. A solvent at 15C with a heat capacity 2.1J/gC is fed into the tank at a rate of 15kg/h. Heated solvent is discharged at the same flow rate. The tank is filled initially with 125kg cold solvent at 10C. The rate of heating the electric coil is 2000W. a. Write a differential equation for energy balance. (1 marks) b. Simplify the equations by inserting suitable values ( 1 marks) c. Solve using the SIMULINK ( 8 marks) 2. (3 marks) Pure water flows into a tank at a rate of 10L/min. The contents of the tank are preserved and mixed well. The contents flow out at a rate of 10L/min. Initially, the tank contained 10kg of salt in 100 liters of water. How much salt will there be in the tank after 30 minutes? 3. ( 2 marks) Pure water flows into a tank at a rate of 8L/min. The contents of the tank are preserved and mixed well, and the contents flow out at a rate of 10L/min. Initially, the tank contained 10kg of salt in 100 liters of water. How much salt will there be in the tank after 30 minutes