A substance that has a fixed volume but lacks a definite shape is called a liquid. Common examples of liquids include water, blood, vinegar, milk, coffee, mercury, bromine, rubbing alcohol, soda and orange juice.
Matter is generally identified based on its defining characteristics that include a rest mass and the physical space, or volume, that it occupies. It can be broadly categorized according to its composition and physical state. Based on composition, matter can be a mixture or a pure substance, and it is then further classified into elements and compounds. Based on physical state, matter can be a solid, liquid or gas.
The three states of matter vary in their physical behaviors. Solids have both definite shape and definite volume, while gases lack both. Liquids retain a fixed volume which does not vary from one container to another. However, the shape that liquids take up is determined by the vessel.
Liquids are composed of closely packed molecules that allow enough room for the particles to still rapidly move around. The bonds between these molecules are stronger compared to gases and weaker compared to solids. Substances that tend to be liquids at room temperature share three general characteristics. Liquids typically contain heavier molecules, asymmetrical structures and intermolecular forces that are neither weak nor strong.