Oil enters a counterflow heat exchanger at 450 k with a mass flow rate of 10 kg/s and exits at 350 k. a separate stream of liquid water enters at 20°c, 5 bar. each stream experiences no significant change in pressure. stray heat transfer with the surroundings of the heat exchanger and kinetic and potential energy effects can be ignored. the specific heat of the oil is constant, c = 2 kj/kg · k. if the designer wants to ensure no water vapor is present in the exiting water stream, what is the minimum mass flow rate for the water, in kg/s?