Two grams of a saturated liquid are converted to a saturated vapor by being heated in a weighted piston–cylinder device arranged to maintain the pressure at 200 kPa. During the phase conversion, the volume of the system increases by 1000 cm³, 5 kJ of heat are required, and the temperature of the substance stays constant at 80°C. Estimate the saturation pressure P_sat of this substance when its temperature is 100°C.