Refrigerant R 134 at 5 bars and 4°C enters a mixing chamber at a steady rate of 2 kg/s. Another source of refrigerant R134 at 6 bars and 50°C is first throttled before it enters the mixing chamber. The mixture leaves the chamber as a saturated liquid at 5 bars. If heat transfer to the chamber occurs at a rate of 4 kJ/s, determine the mass flow rate of refrigerant gas entering the chamber, in kg/s