1) (40 pts) Air is in a piston/cylinder setup at 2000 kPa pressure and 290 K temperature (see below figure). Air reaches 1000 kPa pressure and 400 K after an expansion process during which transferred heat to the air is 100 kJ/(kg air). Determine a) the per unit mass entropy change of air (kJ/kg-K) and b) per unit mass work performed by the air. Air is an ideal gas with variable specific heats. (for air R= 0.287 kJ/kg-K).