Certified Flight Registered Nurse (CFRN) Practice Exam

What gas law states that the total pressure of a gas mixture is the sum of the partial pressures of its individual gases?

1. Henry's law

2. Dalton's law

3. Boyle's law

4. Gay-Lussac's law

The correct answer is: Dalton's law

Dalton's law, also known as Dalton's law of partial pressures, is the principle that describes how the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each individual gas within that mixture. This is based on the understanding that each gas in the mixture behaves independently and contributes to the overall pressure without interfering with each other. In practical terms, this means that if you have a gas mixture composed of several gases, you can determine the total pressure of the mixture by measuring the pressure of each individual gas while it is isolated and then simply adding those values together. This fundamental principle is widely applied in fields such as chemistry, physics, and engineering, particularly in situations involving reactions and conditions where gases interact. The other choices refer to different gas laws. Henry's law concerns the solubility of a gas in a liquid at a given temperature and pressure. Boyle's law relates pressure and volume of a gas at constant temperature, while Gay-Lussac's law connects temperature and pressure of a gas at constant volume. None of these laws addresses the relationship between total pressure and the individual contributions of gases in a mixture, making Dalton's law the correct answer to the question.