A desuperheater is a steady-flow, adiabatic mixing process that mixes superheated water vapor with colder liquid water to produce a stream of saturated water vapor. The superheated water vapor enters the desuperheater at 5MPa, 400 degrees cenitgrade at a mass flow rate of 0.5kg/s. The compressed liquid water enters the desuperheater at 5MPa, 40 degrees centigrade. Water exits the desuperheater as 4.5Mpa saturated vapor. Find the required mass flow rate of the compressed liquid.