A gas mixture contains each gas at the indicated partial pressure. \(\begin{array}{ll}\mathrm{N}_{2} & 217 \text { torr } \\ \mathrm{O}_{2} & 106 \text { torr } \\ \mathrm{He} & 248 \text { torr }\end{array}\) What is the total pressure of the mixture?

When dealing with a gas mixture, it's essential to comprehend that each gas contributes to the overall volume and pressure. The total pressure of the mixture is simply the sum of the individual pressures exerted by each gas. This pressure is what you would measure if you put the mixture into a container and gauged it with a barometer or manometer.

To put it into context, think of a room filled with different musical instruments; each contributes to the overall sound in the room. Similarly, each gas contributes to the total pressure in a container. This concept is particularly useful in practical applications like calculating atmospheric pressure or managing gases in a laboratory setting.

Imagine a potluck dinner where each dish adds to the grand feast. Similarly, in a gas mixture, Dalton's Law of Partial Pressures states that the total pressure exerted is the sum of the partial pressures of each individual gas. This law assumes that the gases do not interact chemically and their particles behave independently.

What does this mean in practice? For instance, if you have a balloon filled with a mix of oxygen and helium, even though the gases have different properties, Dalton's Law allows you to treat their pressures additively. This assumption simplifies complex calculations and is commonly applied in fields like meteorology, respiratory physiology, and engineering.

Calculations involving gas mixtures are akin to balancing a budget with several income sources. You assess each component separately and then tally them up. To calculate the total pressure, you first identify the partial pressure of each constituent gas. These can be found either provided in a problem, as in our example, or calculated from other given variables using the ideal gas law.

Revisiting Our Example

Given the partial pressures for nitrogen, oxygen, and helium, the task resembles a simple addition problem. However, it's crucial to carry out the calculations accurately and pay attention to units, ensuring they are consistent throughout the process to avoid any confusion or error. This straightforward method of addition provides a foundation for more complex problems you may encounter in thermodynamics or chemical engineering.

The behaviour of gases and their interactions in mixtures is governed by a set of principles known as chemistry gas laws. These laws encompass a variety of conditions such as temperature, volume, and pressure, and include Boyle's Law, Charles's Law, and Avogadro's Law, among others. They form the cornerstone of understanding how gases behave under different conditions.

Each law provides a unique insight, like how pressure and volume are inversely related (Boyle's Law) or how volume directly correlates with temperature (Charles's Law). Collectively, these laws enable scientists and engineers to predict and manipulate the behaviour of gases in laboratories and industrial processes, aiding in the advancement of technology and enhancing our daily lives.