What does Avogadro's Law state about gases at the same temperature and pressure?

Avogadro's Law states that under the same temperature and pressure conditions, equal volumes of gases contain an equal number of moles of molecules. This law emphasizes the relationship between the volume of a gas and the number of moles it contains when temperature and pressure are held constant.

Since the law relates directly to the concept of moles, it indicates that regardless of the type of gas, if you have equal volumes, those volumes will contain an identical number of molecules (and thus moles) when conditions are standardized. This principle is crucial for understanding gas behavior and is foundational in stoichiometry and reaction calculations involving gases.

In the context of the other options, while gases may differ in volumes, masses, and their behavior under pressure, Avogadro's Law specifically highlights the equality in the number of moles for equal volumes at a specified temperature and pressure. This makes the correlation of moles the key concept of Avogadro's Law.