Question

Identify the state variables that describe the nature of a gas.

• A. Number of moles
• B. Avogadro's number
• C. Pressure
• D. Volume

Answer 1

Answer: (A), (C), (D)

Volume

The state variables that describe the nature of a gas are related to each other through the ideal gas equation $\text{PV}=n\text{RT}$, where $\text{R}={\text{N}}_{\text{A}}{\text{k}}_{\text{B}}$ is universal gas constant. It is constant for all the gases. So, it does not describe the nature of one particular gas.

Therefore, pressure, volume, temperature, and number of moles describe the state of a gas. But, Avogadro's number (${\text{N}}_{\text{A}}$) is a part of the gas constant, and hence, it won't describe the nature of a gas.