Volume: definition in chemistry
Volume: The amount of three-dimensional space that a substance or object takes up.
The SI unit of volume is the cubic meter (m³), but chemists mostly use liters (L) and milliliters (mL); one milliliter equals one cubic centimeter (cm³). Liquid volumes are measured with graduated cylinders, burettes, pipettes and volumetric flasks. The volume of a gas changes a lot with temperature and pressure, so gas volumes are always compared under stated conditions.
Examples
- 1 liter = 1,000 mL = 1,000 cm³
- A standard soda can holds about 355 mL
- One mole of an ideal gas takes up about 22.4 L at 0 °C and 1 atm
- Water expands by about 9% when it freezes into ice
On the periodic table
The molar volume of the solid elements rises and falls in a repeating pattern across the periods, peaking at the alkali metals, a pattern that helped early chemists build the periodic table.