Air is heated at steady state as it flows through a horizontal, constant area duct. At the inlet, the pressure is 2 bar, the temperature is 300K and the velocity is 87 m/s. At the exit, the pressure and velocity are 1.45 bar and 360 m/s respectively. Assuming ideal gas behavior for air, determine the heat transfer per unit mass of air flowing through the duct in kj/kg.