Calculate the number of chains in a 5 m-long PVC pipe with an inner diameter 5 cm and a thickness of 0.5 cm if the degree of polymerization in 1000. Assume that the chains are equal in length. The density of PVC is 1.4 g/cm3. The molecular weight of PVC monomer is (2 C atoms)(12 g/mol) (3 H atoms)(1 g/mol) (1 Cl atom)(35.5 g/mol)

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 the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct.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.