Water in an open metal drum is to be heated from room temperature (25°C) to 80°C by adding steam slowly enough that all the steam condenses. The drum initially contains 100 kg of water, and steam is supplied at 3.0 bar and 300°C. How many kilograms of steam should be added so that the final temperature of the water in the tank is exactly 80°C? Neglect all heat losses from the water in this calculation.