According to Dalton's Law, what does each gas in a mixture do?

Dalton's Law of Partial Pressures states that in a mixture of non-reacting gases, each gas behaves independently and exerts its own pressure as if it were the only gas present. This means that the pressure exerted by the entire mixture is the sum of the partial pressures of each gas. Thus, the correct understanding is that each gas in the mixture exerts pressure independently of the others.

This principle is fundamental in various applications, including meteorology, respiratory physiology, and engineering, where understanding the behavior of gases is crucial. It allows engineers to calculate the total pressure of a gas mixture by simply adding the individual pressures contributed by each gas, enhancing the predictability and control in processes involving gases.

In contrast, the other options do not align with Dalton's Law. While gases do contribute to the total volume collectively, it’s their pressures that are primarily considered under this law. The reaction of gases to form a compound isn’t a part of Dalton’s Law since that describes a chemical interaction rather than the physical behavior of gases in a mixture. Lastly, the molecular weight of each gas varies depending on the type of gas and is not implied by Dalton's Law, which focuses on pressures rather than molecular properties.