Final answer:
The gas state of matter is where atoms or molecules move freely with enough energy, resulting in no definite shape or volume. Gases have widely spaced particles that collide elastically and can expand to fill their container fully.
Step-by-step explanation:
Describe the Gas State of Matter
The gas state of matter is one where atoms or molecules possess sufficient energy to move freely. In this state, these particles collide with each other randomly and only do so when they happen to cross paths. The forces between atoms or molecules in a gas are too weak to hold them in a fixed position, allowing gases to have no definite shape or volume. The gas particles move in straight lines in various directions until they collide with other molecules or the walls of the container. These collisions are considered elastic, which means the particles 'bounce off' each other, conserving the total kinetic energy of the system. Unlike solids and liquids, gases can expand or contract to fill their container, as they have no fixed shape or volume and the particles are not closely held together.
Gases also differ from solids and liquids in terms of the volume change during phase transitions. While solids and liquids maintain a nearly constant volume when they change state, transitioning from a liquid to a gas can increase the volume of a substance significantly, often by more than a thousand times.