Admission Test for Dental Hygiene (ATDH) Practice

Which of the following statements best describes Dalton's Gas Law?

1. The total pressure by a mixture of gases is equal to the sum of the partial pressures of each of the constituent gases

2. The temperature of a gas is directly proportional to its volume

3. The volume of a gas is inversely related to its pressure

4. The weight of gas depends solely on its temperature

The correct answer is: The total pressure by a mixture of gases is equal to the sum of the partial pressures of each of the constituent gases

Dalton's Gas Law, also known as Dalton's Law of Partial Pressures, states that in a mixture of non-reacting gases, the total pressure exerted by the mixture is equal to the sum of the partial pressures of each individual gas in the mixture. This means that each gas behaves independently and contributes to the overall pressure based on its own properties, irrespective of the other gases present. This concept is crucial in various applications, such as calculating the behavior of gases in respiratory physiology, scuba diving, and atmospheric science. The law assumes ideal gas behavior, meaning it is valid under conditions where gases behave independently and do not react with each other. Other statements pertain to different gas laws, but they do not define Dalton's Law. For instance, the statement about temperature being directly proportional to volume relates to Charles's Law, while the correlation between volume and pressure is described by Boyle's Law. The idea that the weight of gas depends solely on temperature addresses factors that are not encompassed by Dalton's Law specifically. Therefore, understanding that the total pressure in a gas mixture is derived from the sum of each gas's pressure is fundamental to applying Dalton's Law effectively in scientific practice.