PLEASE HELP!!! Which phase change occurs when steam is cooled to 100°C?
condensation
boiling
sublimation
evaporation

The amount of energy needed to change a liquid into a gas, without changing its temperature, is known as the __________.
heat of sublimation
heat of fusion
specific heat
heat of vaporization

In which phase change are hydrogen bonds formed?
boiling
sublimation
evaporation
freezing

The specific heat of a substance is 0.215 J/g°C. How much energy is required to raise the temperature of 20 g of the substance from 72°C to 88°C?
68.8 J
323.4 J
4.3 J
3.4 J