3) During expansion of 1 kg of a fluid the internal energy changes from an initial value of 1162 kJ/kg to a final value of 1025 kJ/kg. If 85 kJ of shaft work are obtained, calculate the quantity and direction of the heat exchange between the fluid and the surroundings. Assume the expansion is frictionless. 4) In a certain non-flow process with air as the working fluid, 950 kJ are removed from the system and the internal energy decreases by 180 kJ. Is the process an expansion or compression? What work is performed? 13