What defines an extensive property in thermodynamics?

An extensive property in thermodynamics is one that depends on the amount of substance present in the system. This characteristic means that as the size or extent of the system changes—whether by increasing the quantity of material or enlarging the volume—the value of the extensive property will change accordingly. Examples of extensive properties include mass, volume, and total internal energy.

In contrast to extensive properties, intensive properties do not change with the amount of substance and remain the same regardless of the system's size. Understanding this distinction is essential when analyzing thermodynamic systems and their behaviors under various conditions.