Gas density calculator
Rearranging PV = nRT for mass per unit volume gives density = P M / (R T).
g/mol
Dry air averages 28.96 g/mol.
Density
1.2039kg/m3
- Same figure
- 1.2039 g/L
- Specific volume
- 0.830 632 m3/kg
Show the working
- Molar mass = 28.96
- Pressure = 101 325
- Temperature = 20
- tk = 20 + 273.15 = 293.15
- Density = 101 325 * 28.96 / 1000 / (Rgas * 293.15) = 1.2039
- Same figure = 1.2039 = 1.2039
- Specific volume = 1 / 1.2039 = 0.830 632
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- density = P M / (R T), with M in kg/mol
Air at 20 degrees Celsius and one atmosphere comes out at 1.204 kg/m3, which is the figure used throughout aerodynamics.