Which of the following thermodynamic properties apply to refrigerants?

All of these properties—entropy, density, and volume—are essential thermodynamic properties that apply to refrigerants.

Entropy is a measure of the disorder or randomness in a system, and it plays a crucial role in understanding the efficiency and performance of refrigerants during refrigeration cycles. For instance, changes in entropy help to determine how much work can be extracted from or added to a refrigerant during phase changes.

Density refers to the mass per unit volume of a refrigerant, which is critical for understanding the behavior of a refrigerant under different pressures and temperatures. It affects how refrigerants flow and how much heat they can carry away.

Volume is an important property because it is directly related to both the pressure and temperature of the refrigerant. Changes in volume during phase transitions (like evaporation and condensation) are fundamental to the operation of refrigeration and air conditioning systems.

Combining these properties provides a comprehensive understanding of how refrigerants behave in various applications, making it essential to consider all of them in thermodynamic analyses. Therefore, the most complete and accurate answer includes all of these properties, as they together describe the fundamental behavior of refrigerants in thermodynamic cycles.