Rectification of a heptane–ethyl benzene mixture. a saturated liquid feed of 200 mol/h at the boiling point containing 42 mol % heptane and 58% ethyl benzene is to be fractionated at 101.32 kpa abs to give a distillate containing 97 mol % heptane and a bottoms containing 1.1 mol % heptane. the reflux ratio used is 2.5: 1. calculate the mol/h distillate, mol/h bottoms, theoretical number of trays, and the feed tray number. equilibrium data are given below at 101.32 kpa abs pressure for the mole fraction n-heptane h and yh:

To save energy, the air supply to a 2000 ft office has been shut off overnight and the room temperature has dropped to 40°f. in the morning, the thermostat is reset to 70°f and warm air at 120 f begins to flov in at 200ft'/min. the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct. the air pressure is nearly 1 atm everywhere. ignoring heat transfer with the surroundings and kinetic and potential energy effects, estimate how long it takes for the room temperature to reach 70°f. plot the room temperature as a function of time.