Which process releases 2260 joules of heat
energy per gram of water into the environment?
(1) melting (3) condensation
(2) freezing (4) evaporation

The correct answer is (4) 

Evaporation or vaporization is a change of phase of a substance from liquid to gas (vapor).

For water, this process requires the  addition of 2260 Joules of heat energy for every gram of water that evaporates (vaporizes). The added energy remains in the water vapor (potential energy) and will be released in the process of condensation.

This heat energy that is required to change water into vapor is called the latent heat of vaporization.

Latent heat of a material is defined as the energy required to change the state of a material without changing the material's temperature.