Liquid Definition and Examples (Chemistry)

Liquids: State of Matter That Flows

The natural surface tension of liquids causes them to form spherical droplets, which minimize surface area.
The natural surface tension of liquids causes them to form spherical droplets, which minimize surface area. Westend61 / Getty Images

Liquid Definition

A liquid is one of the states of matter. The particles in a liquid are free to flow, so while a liquid has a definite volume, it does not have a definite shape. Liquids consists of atoms or molecules that are connected by intermolecular bonds.

Examples of Liquids

At room temperature, examples of liquids include water, mercury, vegetable oil, ethanol. Mercury is the only metallic element that is a liquid at room temperature, although francium, cesium, gallium, and rubidium liquefy at slightly elevated temperatures.

Aside from mercury, the only liquid element at room temperature is bromine. The most abundant liquid on Earth is water.

Properties of Liquids

  • Liquids are nearly incompressible fluids. In other words, even under pressure, their value only decreases slightly.
  • The density of a liquid is affected by pressure, but generally the change in density is small. The density of a liquid sample is fairly constant throughout. The density of a liquid is higher than that of its gas and usually lower than that of its solid form.
  • Liquids, like gases, take the shape of their container. However, a liquid cannot disperse to fill a container (which is a property of a gas).
  • Liquids have surface tension, which leads to wetting.
  • Although liquids are common on Earth, this state of matter is relatively rare in the universe because liquids only exist over a narrow temperature and pressure range. Most matter consists of gases and plasma.
  • Particles in a liquid have greater freedom of movement than in a solid.
  • When two liquids are placed into the same container, they may either mix (be miscible) or not (be immiscible). Examples of two miscible liquids are water and ethanol. Oil and water are immiscible liquids.