How many calories are released when 58.4 g of steam at 144 C is cooled to -37.6 C?

Expert Answers
justaguide eNotes educator| Certified Educator

To find the heat released when 58.4 g of steam at 144 C is cooled to ice at -37.6 C requires the heat of vaporization of water that is 2257 kJ/kg, the heat of fusion of water that is 333.55 kJ/kg and the specific heat of steam that is 1.996 kJ/kg*K, the specific heat of water that is 4.187 kJ/kg*K and the specific heat of ice that is 2.108 kJ/kg*K

When steam at 144 C is cooled first the temperature drops to 100 C, at this temperature there is a change in phase from vapor to liquid, the water then cools till a temperature 0 C is reached where the phase changes from liquid to solid and then the ice continues to cool till -37.6 C.

The total heat released is (58.4/1000)(44*1.996 + 2257 + 100*4.187 + 333.55 + 37.6*2.108) = 185.4 kJ or 44.32 kCal.

A total amount of heat equal to 44.32 kilo calories is required to convert 58.4 g steam at 144 C to ice at -37.6 C.