Which term best describes mass per unit volume of a substance?

• A. Density
• B. Characteristic Property
• C. Mean
• D. Solution

Answer: (A)

Density is mass per unit volume. It tells you how tightly matter is packed in a material. You find it by dividing the mass by the volume (density = mass/volume). Common units are g/cm^3 for solids and liquids or kg/m^3 in SI. Temperature and pressure can affect density, especially for gases.

This is distinct from a mean, which is just an average of numbers, and from a solution, which is a homogeneous mixture. It’s also not just a broad category like a characteristic property, which describes how a substance behaves or is identified in general; density is the specific quantity that measures how much matter occupies a given space.