Dichlorodifluoromethane, also known as Freon-12 or R-12, was a commonly used refrigerant prior to the mid-1990s (when its production was banned in the US due to concerns about its effect on the ozone layer). Given that the constant pressure heat capacity of R-12 is 74 J·mol-1·K-1, determine the following:

a) The efficiency of a Carnot refrigerator operating with R-12 between 25.0 ºC and 5.0 ºC.

b) The energy (in kJ) that is removed as heat from this system when the Carnot refrigerator from part a) contains 340. g of R-12. Assume the heat is removed in a constant pressure process.

c) Compare your answer from part b) to the energy removed as heat from this system if the Carnot refrigerator contained an equal mass of air (Cp,m = 29.1 J·mol-1·K-1, molar mass ?29 g·mol-1). Do your answers show why R-12 is/was a superior coolant to air? Why or why not?