What does Dalton's Law explain about gas mixtures?

Dalton's Law describes the behavior of gas mixtures and states that the total pressure exerted by a gas mixture is equal to the sum of the partial pressures of each individual gas in the mixture. Each gas in the mixture contributes to the total pressure independently, based on its own concentration and properties, regardless of the presence of other gases.

This principle is particularly important in SCUBA diving, as divers need to understand how the pressures of different gases, like nitrogen and oxygen, combine under various depths. When a diver descends, the increased ambient pressure causes the partial pressures of each gas in their breathing mix to increase. Monitoring these pressures is crucial for preventing conditions such as nitrogen narcosis or decompression sickness.

The other options do not accurately capture Dalton's Law. For example, a focus solely on the heaviest gas does not account for how all gases in the mixture interact. Additionally, the relationship of gas pressure to volume describes Boyle's Law, not Dalton's Law. Lastly, ambient pressure is indeed a critical factor in gas mixtures; it affects how the gases behave underwater. Thus, the emphasis on the sum of the partial pressures in Dalton's Law provides a foundational understanding necessary for safe diving practices.