Air - Gas Encyclopedia Air Liquide

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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)

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Molecular weight

28.96
g/mol
Content in dry air

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Critical Point

Temperature

- 140.7
°C
- 221.26 °F 132.45 K
Pressure

37.74
bar
3.774E6 pa 547.3722 lbf/in2 37.2465 Atm 3774 Kpa 2.8307E4 mmHg
Density

316.61
kg/m³
19.7653 lb/ft³

Triple Point

Temperature

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Pressure

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Pressure 1.013 bar

Melting point

- 214
°C
- 353.2 °F 59.15 K
Latent heat of fusion (at melting point)

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Solid density

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Pressure 1.013 bar

Liquid density

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Boiling point

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Latent heat of vaporization (at boiling point)

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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

1.8447E-4
Po
18.447 µPa.s 1.8447E-5 PA.S 1.2396E-5 lb/ft/s
Gas density at boiling point

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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

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Solubility in water

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Specific gravity

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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

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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

in standard conditions (1,013 bar, 15°C)

m3(Volume)

kg(Mass)

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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

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Safety & Compatibility

Information to safely use this molecule

Major hazards
Material compatibility

Safety

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 NBR

Satisfactory
Chloroprene

Satisfactory
Silicone

Satisfactory
Perfluoroelastomers

Satisfactory
Fluoroelastomers

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.

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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).