Final answer:
Changes of state, like between liquid and gas, involve the absorption or release of energy. During this process, energy changes occur within the substance's atoms influencing its phase without altering atoms themselves.
Step-by-step explanation:
The changes of state between a liquid and a gas require the input or withdrawal of energy. These transitions are known as phase changes. When a substance, such as water, changes from a liquid to a gas (evaporation), energy is absorbed from the surroundings to overcome intermolecular forces that keep the water molecules together. In contrast, when a substance changes from gas to liquid (condensation), energy is released into the surroundings as the intermolecular forces re-establish. In both cases, the state change doesn't involve the changing of atoms themselves, instead, it's the energy and motion of those atoms that are altered.
Learn more about Changes of State