What does Dalton's Law state about the pressure of gases?

Dalton's Law states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each individual gas in the mixture. This principle applies to ideal gases and is fundamental in understanding how gases behave when mixed. Each gas in the mixture contributes to the total pressure in a way that is independent of the other gases, provided the temperature and volume remain constant.

Given this context, the correct answer highlights that the total pressure can be determined simply by adding together the pressures that each gas would exert if it occupied the volume alone. This is crucial for various applications, including calculations in chemistry and physics involving gas mixtures, such as understanding how gases interact in the atmosphere or in controlled environments.

The other options do not accurately represent Dalton's Law. One suggests a relationship between pressure and temperature that relates to Gay-Lussac's Law, while another describes the inverse relationship between pressure and volume, which pertains to Boyle's Law. The final choice incorrectly implies a limitation on gas presence in a volume, which contradicts the very concept of gas mixtures foundational to Dalton's Law.