Which physical law applies when calculating the partial pressures of gases?

When calculating the partial pressures of gases, Dalton's Law of Partial Pressures is the relevant physical law. According to this law, in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of each individual gas in the mixture. This means that each gas behaves independently, and its partial pressure can be calculated based on its proportion in the total volume of gas at a given temperature and total pressure.

In the context of diving and using Nitrox mixtures, understanding Dalton's Law helps divers assess the amount of oxygen and nitrogen, or other gases, present in the mix, allowing for proper planning to avoid nitrogen narcosis and oxygen toxicity. By applying this law, divers can calculate and manage the safe limits for breathing gases at specific depths, taking into account how each gas contributes to the overall pressure and its biological effects.

The other laws mentioned address different aspects of gas behavior. Boyle’s Law deals with the relationship between pressure and volume at constant temperature, Charles's Law involves the relationship between temperature and volume at constant pressure, and Henry's Law describes the solubility of gases in liquids at a fixed temperature and increasing pressure. While these laws are essential in the field of diving and gas laws,