What characteristics must be held constant when applying Avogadro's Law?

Avogadro's Law states that equal volumes of gases, at the same temperature and pressure, contain an equal number of molecules. This implies that the law is fundamentally about the relationship between the volume of a gas and the number of moles of that gas.

When applying Avogadro's Law, it is essential to maintain constant temperature and pressure because any variation in these parameters can affect gas behavior independently of the number of moles involved. Therefore, while the number of moles is being studied in relation to the volume, the temperature and pressure must remain unchanged to isolate the relationship that Avogadro’s Law aims to demonstrate. By keeping temperature and pressure constant, the relationship can accurately show that the volume of gas is directly proportional to the number of moles present, allowing deeper insights into gas behavior under fixed conditions.