State how much energy is transferred in each of the following cases:
a. 2 grams of steam at 100 degrees Celsius condenses to water at 100
b. 2 grams of boiling water at 100 degrees Celsius cools to ice water at 0
c. 2 grams of ice water at 0 degrees Celsius freezes to ice at 0 degrees
d. 2 grams of steam at 100 degrees Celsius turns to ice at 0 degrees