Which property would be considered extensive?

Extensive properties are characteristics of a system that depend on the size or amount of matter present in that system. In the context of the question, mass is a clear example of an extensive property. As you increase the quantity of a substance, its mass increases proportionally; for instance, doubling the amount of a substance will double its mass.

In contrast, properties like density, temperature, and pressure do not change with the amount of material present. Density is a ratio of mass to volume and remains constant regardless of how much substance is measured. Similarly, temperature and pressure describe the state of a system and do not inherently depend on the size or quantity of the material involved.

Understanding the distinction between extensive and intensive properties is vital in thermodynamics, as it helps in characterizing and predicting the behavior of different systems under various conditions. Thus, mass is recognized as extensive because it directly correlates with the quantity of material present.