A gas mixture is a combination of two or more gases that are physically mixed together but not chemically combined. Each gas in the mixture retains its individual properties, such as pressure and temperature. Common examples of gas mixtures include the air we breathe, which is primarily composed of nitrogen, oxygen, and small amounts of other gases. Gas mixtures can be found in various applications, including industrial processes, medical treatments, and environmental studies. For instance, helium and oxygen are often mixed for deep-sea diving to prevent nitrogen narcosis. Understanding gas mixtures is essential for fields like chemistry, engineering, and environmental science.