A closed system consisting of 0.13 lbmol of air undergoes a polytropic process from a pressure of 14 psia and specific volume of 11.50 ft3/lb to a final state of 83 psia and specific volume of 3.98 ft3/lb. Determine the amount of energy transfer by work, in Btu, for the process. The molar mass of air is 28.97 lb/mol.