Final answer:
A substance is in the liquid state if it takes the shape of its container, has a definite volume but no definite shape, and has particles that are mobile but still in close contact.
Step-by-step explanation:
A substance is said to be in the liquid state if it takes the shape of its container. The particles of a liquid have enough energy to partially overcome intermolecular interactions, allowing them to move around each other while still in close contact. This means that a liquid has a definite volume but no definite shape.
Unlike solids, which are rigid and have both a definite shape and volume, liquids adapt their shape to fit the container they are in. The particles in a liquid state are attracted strongly enough to not be easily compressed, but they can move around within the liquid, allowing it to flow and take the shape of the container.