Which thermodynamic relationship reflects the change in volume of a system?

The choice that accurately reflects the change in volume of a system is characterized by the relationship involving the partial derivative of the Gibbs free energy with respect to pressure at constant temperature. This specific relationship, (∂G/∂p) _T = V, indicates that the change in Gibbs free energy (G) with respect to changes in pressure (p) at constant temperature (T) directly yields the volume (V) of the system.

This is rooted in the fundamental thermodynamic relationships and definitions, where the Gibbs free energy is a potential energy function dependent on pressure and temperature. The volume of the system plays a central role in describing how the system responds to changes in external pressure, thus connecting macroscopic properties with microscopic behaviors. By taking this derivative, we obtain a direct expression for the system's volume, revealing how much the system would expand or contract under varying pressures while maintaining a constant temperature.

Other options pivot around different thermodynamic relationships, focusing on different aspects like the relationship between Gibbs free energy, enthalpy, and entropy, but do not address the change in volume directly with respect to changes in pressure, which is the essence of option B.