What is the density of Air?

The density of air at standard temperature and pressure (STP) is typically around 1.29 g/L. This value is derived from the average composition of air, which consists mainly of nitrogen (approximately 78%) and oxygen (approximately 21%), along with trace amounts of other gases. At STP, the mass of a liter of air is influenced by this molecular composition and the ideal gas law, which predicts how gases behave in relation to volume and temperature.

Understanding the density of air is crucial in various medical and industrial applications, such as administering oxygen therapy, where the density of the gas affects how it is delivered and its behavior in different environments. The other values provided do not accurately represent the standard density of air. Thus, the correct choice reflects the standard density measurement used in scientific and practical contexts.