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Air

Air is a mixture of several molecules and atoms composing the earth atmosphere. Main components are nitrogen (78.09%vol in dry air) , oxygen (20.95%vol in dry air) and argon (0,93%vol in dry air). Small quantities of helium, neon, xenon and krypton are also to be found. Carbon dioxide, water, methane, ozone as well as other molecules involved into natural and human (local) activities are also present in the atmosphere. Those quantities vary from on site to another and with time.

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Air

Air is a mixture of several molecules and atoms composing the earth atmosphere. Main components are nitrogen (78.09%vol in dry air) , oxygen (20.95%vol in dry air) and argon (0,93%vol in dry air). Small quantities of helium, neon, xenon and krypton are also to be found. Carbon dioxide, water, methane, ozone as well as other molecules involved into natural and human (local) activities are also present in the atmosphere. Those quantities vary from on site to another and with time.

Air

Physical Properties

Under solid (grey), liquid (blue) and vapor states (white) along the equilibrium curves

  • General properties
  • Solid phase
  • Liquid Phase
  • Gas Phase
(P)
log(P)
Download
  • Molecular weight
    28.96
    g/mol
  • Content in air
    /

Critical Point

  • Temperature
    - 140.6
    °C
    - 221.08 °F 132.55 K
  • Pressure
    37.663
    bar
    3.7663E6 pa 546.2554 lbf/in2 37.1705 Atm 3766.3 Kpa 2.825E4 mmHg
  • Density
    319.93
    kg/m³
    19.9725 lb/ft³

Triple Point

  • Temperature
    /
  • Pressure
    /
Pressure 1.013 bar
  • Melting point
    - 214
    °C
    - 353.2 °F 59.15 K
  • Latent heat of fusion (at melting point)
    /
  • Solid density
    /
Pressure 1.013 bar
  • Liquid density
    /
  • Boiling point
    /
  • Latent heat of vaporization (at boiling point)
    /
Pressure1.013barTemperature
  • Compressibility factor Z
    9.994E-1
    9.996E-1
    9.997E-1
  • Cp/Cv ratio γ
    1.4028
    1.4022
    1.4018
  • Dynamic viscosity
    1.7218E-4
    Po
    17.218 µPa.s 1.7218E-5 PA.S 1.157E-5 lb/ft/s
    1.7962E-4
    Po
    17.962 µPa.s 1.7962E-5 PA.S 1.207E-5 lb/ft/s
    1.849E-4
    Po
    18.49 µPa.s 1.849E-5 PA.S 1.2425E-5 lb/ft/s
  • Gas density at boiling point
    /
    /
    /
  • Gas density
    1.292
    kg/m³
    8.0657E-2 lb/ft³
    1.225
    kg/m³
    7.6474E-2 lb/ft³
    1.184
    kg/m³
    7.3915E-2 lb/ft³
  • Heat capacity at constant pressure Cp
    1.0059
    kJ/(kg.K)
    2.4042E-1 BTU/lb∙°F 1005.905 J/kg∙K 2.4042E-1 kcal/kg∙K
    1.0062
    kJ/(kg.K)
    2.4049E-1 BTU/lb∙°F 1006.215 J/kg∙K 2.4049E-1 kcal/kg∙K
    1.0065
    kJ/(kg.K)
    2.4057E-1 BTU/lb∙°F 1006.526 J/kg∙K 2.4057E-1 kcal/kg∙K
  • Heat capacity at constant volume Cv
    7.1709E-1
    kJ/(kg.K)
    1.7139E-1 BTU/lb∙°F 717.093 J/kg∙K 1.7139E-1 kcal/kg∙K
    7.1761E-1
    kJ/(kg.K)
    1.7151E-1 BTU/lb∙°F 717.61 J/kg∙K 1.7151E-1 kcal/kg∙K
    7.1803E-1
    kJ/(kg.K)
    1.7161E-1 BTU/lb∙°F 718.025 J/kg∙K 1.7161E-1 kcal/kg∙K
  • Liquid (at boiling point)/gas equivalent
    /
    /
    /
  • Solubility in water
    /
    /
    /
  • Specific gravity
    /
    /
    /
  • Specific volume
    7.738E-1
    m³/kg
    12.3951 ft³/lb
    8.164E-1
    m³/kg
    13.0775 ft³/lb
    8.448E-1
    m³/kg
    13.5324 ft³/lb
  • Thermal conductivity
    24.36
    mW/m∙K
    1.4084E-2 Btu/ft/h/°F 2.096E-1 cal/hour∙cm∙°C 5.8222E-5 cal/s∙cm∙°C 2.436E-2 W/(m∙K)
    25.499
    mW/m∙K
    1.4743E-2 Btu/ft/h/°F 2.194E-1 cal/hour∙cm∙°C 6.0944E-5 cal/s∙cm∙°C 2.5499E-2 W/(m∙K)
    26.247
    mW/m∙K
    1.5175E-2 Btu/ft/h/°F 2.2584E-1 cal/hour∙cm∙°C 6.2732E-5 cal/s∙cm∙°C 2.6247E-2 W/(m∙K)
  • Vapor pressure
    /
    /
    /
Air

Liquid / Gas Volumes

Calculate a liquid or gas volume or a mass

Liquid Phase

At boiling point at 1.013 bar

m3(Volume)
kg(Mass)

Gas Phase

at 1.013 bar and boiling point

m3(Volume)
kg(Mass)
Air

Applications

Examples of uses of this molecule in Industry and Healthcare

Chemicals

Air is used as oxygen source for the synthesis of many organic compounds, such as acrylonitrile and acrylic acid from propylene. Those two compounds are used for the production of plastics.

Chemicals

Hospital care

Drug: air is used to supply air delivery for the ventilation of patients.

Hospital care

Laboratories & Research Centers

Pure air is used to calibrate and run environmental emission monitoring equipement, industrial hygiene monitors and trace impurity analyzers. It is used as a balance gas for many calibration mixtures. Air is also used as combustion oxidizer for gas chromatograph flame ionization detectors and atomic absorption spectrometers.

Laboratories & Research Centers

Metal

Hot air is blown into blast furnaces for the production of liquid metal from iron oxides.

Metal

Oil & Gas

Air is used as oxidizing compound in Claus process to convert sulfur into sulfur dioxide. Compressed air is widely used as an energy for various equipment and instrumentation.

Oil & Gas
Air

Safety

Information to safely use this molecule

  • Major hazards
  • Material compatibility
  • GHS04
    Gas under pressure

Odor

none

Metals

  • Aluminium
    Satisfactory
  • Brass
    Satisfactory
  • Monel
    Satisfactory
  • Copper
    Satisfactory
  • Ferritic Steel
    Satisfactory
    corrosive in presence of water
  • Stainless steel
    Satisfactory
  • Zinc
    Satisfactory
  • Titanium
    no data

Plastics

  • Polytetrafluoroethylene
    Satisfactory
  • Polychlorotrifluoroethylene
    Satisfactory
  • Polyvinylidene fluoride
    Satisfactory
  • Polyvinyl chloride
    Satisfactory
  • Ethylene tetrafluoroethylene
    Satisfactory
  • Polycarbonate
    Satisfactory
  • Polyamide
    Satisfactory
  • Polypropylene
    Satisfactory

Elastomers

  • Buthyl (isobutene- isoprene) rubber
    Satisfactory
  • Nitrile rubber
    Satisfactory
  • Chloroprene
    Satisfactory
  • Chlorofluorocarbons
    Satisfactory
  • Silicon
    Satisfactory
  • Perfluoroelastomers
    Satisfactory
  • Fluoroelastomers
    Satisfactory
  • Nitrile rubber
    Satisfactory
  • Neoprene
    Satisfactory
  • Polyurethane
    Satisfactory
  • Ethylene-Propylene
    Satisfactory

Lubricants

  • Hydrocarbon based lubricant
    Satisfactory
  • Fluorocarbon based lubricant
    Satisfactory

Materials compatibility

Recommendations : Air Liquide has gathered data on the compatibility of gases with materials to assist you in evaluating which materials to use for a gas system. Although the information has been compiled from what Air Liquide believes are reliable sources (International Standards: Compatibility of cylinder and valve materials with gas content; Part 1- Metallic materials: ISO11114-1 (March 2012), Part 2 - Non-metallic materials: ISO11114-2 (April 2013), it must be used with extreme caution and engineering judgement. No raw data such as these can cover all conditions of concentration, temperature, humidity, impurities and aeration. It is therefore recommended that this table is only used to identify possible materials for applications at high pressure and ambient temperature. Extensive investigation and testing under the specific conditions of use need to be carried out to validate a material selection for a given application. Contact the regional Air Liquide team for expertise service.

Air

Learn More

General information

More information

The initial measurements of the constituents of air, with the exception of argon, were improved and summarized in the early 1800s by John Dalton. Earth's atmosphere is 78.09 % nitrogen, 20.94 % oxygen, 0.93 % argon, and 0.04 % carbon dioxide with very small percentages of other elements (neon, helium, krypton, methane, hydrogen, xenon and radon).