Final answer:
A substance in a gaseous state that occupies a large volume relative to its mass is called a gas, characterized by particles with high kinetic energy and significant expansion from other states of matter.
Step-by-step explanation:
The term used to describe a substance in a gaseous state that is dispersed and occupies a large volume relative to its mass is simply referred to as a gas. According to the Kinetic Theory of Gases, particles in a gas have enough kinetic energy to overcome intermolecular forces, allowing them to move about randomly and fill the entire volume of their container. This state of matter is characterized by high compressibility and the ability to expand greatly when changing from a liquid or solid state, with volumes typically increasing by a factor of 1,000 or more.