posted by xam .
five hundred kcal of heat is added to 2-kg of water at 80 degree Celsius. how much steam is produced?
First, you need to transfer 2*1.0*20 = 40 kcal to heat the 2kg 20 degrees to the boiling point. That leaves 460 kcal for vaporization.
Amount of steam produced = (460 cal)/(540 kcal/kg) = 0.852 kg