A six liter (6 L) pot is fitted with a heavy lid that allows a maximum of 200 kPa of absolute pressure. Heat is added to the pot to boil the water. As the liquid boils, mass (in the form of saturated steam) is released from the system to maintain a constant pressure of 200 kPa. If the pot is initially full of saturated water at 200 kPa, how much energy must be added to the pot before the total mass of the water has been reduced by half?