Which of the following is an intensive property?

• A. Mass
• B. Volume
• C. Density
• D. Amount of substance

Answer: (C)

Intensive properties are those that do not depend on how much material you have. Density is one of them because it’s defined as mass per unit volume. For a given substance at the same conditions, the density stays the same whether you have a tiny drop or a large block—the mass and the volume both scale, leaving their ratio unchanged. That intrinsic value is what makes density an intensive property.

Mass and volume are extensive properties; they change when you change the amount of material. If you double the sample, you typically double the mass and double the volume as well. The amount of substance (the number of moles) also grows with sample size, so it’s extensive too. Since only density remains constant with changes in sample size, it fits the description of an intensive property.