An uninsulated cylinder fitted with a piston contains air at 500 kpa, 200◦c, at which point the volume is 10 l. the external force on the piston is now varied in such a manner that the air expands to 150 kpa, 25 l volume. it is claimed that in this process, the air produces 70% of the work that would have re- sulted from a reversible adiabatic expansion from the same initial pressure and temperature to the same final pressure. room temperature is 20◦c. what is the amount of work claimed?