As we saw in the sample calculation earlier in this post, standard air density at IUPAC STD conditions is - 1.4304 kg/m 3įor other standard conditions, you can quickly get the standard air density values from the table over here. Often, you can choose to work with standard temperature and pressure conditions when performing engineering calculations which involve gas volume or volumetric flow rate.Įven for air, standard density is widely used for engineering calculations. Refer to this sample calculation of air compressibility factor as a quick-start guide.Density is a measure of the amount of mass contained in a unit of volume.The general trend is that most gases are less dense than liquids, which are in turn less dense than solids, but there are numerous exceptions. For a more accurate calculation of air density, you would also need to use the correct molecular weight based on air composition and compressibility factor which you can estimate from this table. Heres a table of densities of common substances, including several gases, liquids, and solids.For quick calculations, use this air density calculator to get a quick estimate based on temperature and pressure.You can use this same equation to calculate the density for any real gas when you know its molecular weight and the compressibility (Z) factor. For this reason, the table lists density from lowest to highest and includes the state of matter. The general trend is that most gases are less dense than liquids, which are in turn less dense than solids, but there are numerous exceptions. Alternatively, you can also use this calculator when working with natural gas.Īir density at STP = ρ = P×MW/(Z×R×T) = 100×1000×(28.85/1000)/(0.8777×8.413×(273.16+0)) Air density at STP (ρ) = 1.4304 kg/m 3 The density of air depends on many factors and can vary in different places. Density is a measure of the amount of mass contained in a unit of volume. Refer this table to get air compressibility factor at given temperature and pressure. ![]() Let's try this equation to calculate the density of air at standard temperature and pressure conditions.Īir Molecular weight (MW) = 28.85 gm/mol Universal gas constant (R) = 8.314 J/K Physical properties of air can be represented by the real gas equation, which is the modified version of ideal gas equation. Since water vapor has a lower molecular weight than nitrogen and oxygen, the presence of water vapor decreases the overall molecular weight of the air, resulting in a lower air density. When water vapor is present in the air, it displaces some of the nitrogen and oxygen molecules, which are the main components of dry air. Similarly, as air pressure increases, the air molecules are compressed and packed closer together, resulting in an increase in air density. ![]() As air temperature increases, the air molecules move faster and spread out, resulting in a decrease in air density. However, as the temperature and pressure change, the density of air also changes. It describes how closely packed the air molecules are in a given space.Īt a given temperature and pressure, the density of dry air is relatively constant. Air density is a measure of the mass of air per unit volume, typically expressed in kilograms per cubic meter (kg/m³) or pounds per cubic foot (lb/ft³).
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