What is the mass per unit volume of a substance called?

The mass per unit volume of a substance is called its density. Density is typically expressed in units such as kilograms per cubic meter (kg/m³) in the International System of Units (SI) or grams per cubic centimeter (g/cm³) in other systems of measurement. It represents how much mass is contained within a given volume of a substance and is a fundamental property used to characterize and compare different materials. The formula for density is:

Density (ρ) = Mass (m) / Volume (V)

Where:

Density (ρ) is measured in units of mass per unit volume (e.g., kg/m³ or g/cm³).
Mass (m) is the amount of substance in kilograms (kg) or grams (g).
Volume (V) is the amount of space the substance occupies in cubic meters (m³) or cubic centimeters (cm³).
Density is a valuable property in various scientific and engineering applications, as it can help determine the behavior, buoyancy, and suitability of materials for specific purposes.