A well-insulated piston-cylinder, fitted with a paddle wheel, contains air, an ideal gas. A freely- moving, frictionless piston maintains the air at a constant pressure of 300 kPa. The paddle wheel is turned until the air, initially at 300 K, has doubled in volume. Answer the following assuming air has constant properties at a reasonable average temperature of your choosing. Give reason for the average temperature you choose. a) How much work, per unit mass of air, does the paddle wheel do on the system? b) What is the change in specific entropy of the air during this process?