What physical quantity does the 'n' in the ideal gas law represent?

In the ideal gas law, represented by the equation PV = nRT, the 'n' denotes the number of moles of the gas. This is a crucial component of the equation because it relates the amount of substance present in the gas, allowing us to quantify how the gas behaves under various conditions of pressure (P), volume (V), and temperature (T).

The number of moles serves as a bridge between the microscopic properties of gas molecules and the macroscopic observables that we measure, such as pressure and volume. Utilizing the quantity of moles enables calculations that predict how a gas will react to changes in temperature or pressure, adhering to the assumptions of the ideal gas model, which simplifies complex behaviors into manageable relationships.

The other choices represent different properties of gases: volume indicates the space occupied by the gas, pressure quantifies the force of the gas particles colliding with the walls of their container, and temperature is a measure of the average kinetic energy of the gas molecules. Each of these factors plays a role in the behavior of gases as described by the ideal gas law, but it is the number of moles that directly relates to the quantity of gas present, making 'n' essential for calculations involving the law.