Classifying properties: Which of the following is an extensive property of a thermodynamic system?

Introduction / Context:
Thermodynamic properties are either intensive (independent of system size) or extensive (scale with the amount of substance). Correct classification is essential for setting up balances and for forming specific (intensive) properties by normalization.

Given Data / Assumptions:

• System can be subdivided into identical parts.
• Properties considered: Pressure, Volume, Temperature, Density, Specific volume.

Concept / Approach:

Extensive properties are additive. If we combine two identical subsystems, total value doubles. Volume adds directly (V_total = V1 + V2), making it extensive. By contrast, pressure, temperature, density, and specific volume are intensive; they do not simply add when systems are combined at equilibrium.

Step-by-Step Solution:

Verification / Alternative check:

Dimensional reasoning: volume scales with length^3 of the system size, confirming extensivity; intensive properties are size-independent.

Why Other Options Are Wrong:

Pressure and temperature are equilibrating variables, not additive.Density and specific volume are derived intensives (mass-normalized or volume-normalized quantities).

Common Pitfalls:

Confusing total energy (extensive) with specific energy (intensive); always check if the property adds when systems are merged.

Final Answer:

Volume