posted by Tyler .
500 calories of heat is added to 2.0 g of water at 80 degrees Celsius. How much steam is produced?
2.0 * 20 = 40 calories will be needed to raise the temperature to the boiling point of 100 C. That will leave 460 calories for vaporization. The heat of vaporization of water is 540 cal/g.
460/540 g will vaporize.