In the ideal gas law PV = nRT, what does 'n' represent?

• A. Pressure of the gas
• B. Volume of the gas
• C. Amount of substance in moles
• D. Gas constant

Answer: (C)

In the ideal gas law equation PV = nRT, 'n' represents the amount of substance in moles. This is a crucial component of the equation, as it quantifies the number of particles in the gas. When dealing with gases, understanding the amount of substance is significant because it directly affects the pressure and volume of the gas.

In this equation, pressure (P) is represented in units such as atmospheres or pascals, volume (V) is expressed in liters or cubic meters, the ideal gas constant (R) has different values depending on the units used, and temperature (T) is typically measured in Kelvin. The relationship expressed in the ideal gas law illustrates how these variables are interrelated, and 'n' specifically allows for the calculation of the gas properties based on the number of moles present.

Considering the definitions of the other options: the pressure and volume of the gas are represented by P and V, respectively, while the gas constant R is a constant that relates the energy scale to temperature and is not a variable representing a quantity of substance. Thus, 'n' as the number of moles is essential for defining the system's state fully.