Chemical Property of Helium
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Chemical Property:
- Appearance/Colour:COLOURLESS, ODOURLESS, REFRIGERATED, LIQUEFIED GAS
- Melting Point:-272.2 °C(lit.)
- Boiling Point:-268.934 °C(lit.)
- Flash Point:none
- PSA：0.00000
- Density:0.1785（0℃）
- LogP:0.00000
- Water Solubility.:8.61mL/1000g H2O (101.32kPa, 0°C) [KIR78]; Henry’s law constants, k×10?4: 9.856 (104°C), 6.739 (149.4°C), 2.524 (250.6°C), 1.796 (275.1°C) [POT78]
- Hydrogen Bond Donor Count:0
- Hydrogen Bond Acceptor Count:0
- Rotatable Bond Count:0
- Exact Mass:4.002603254
- Heavy Atom Count:1
- Complexity:0
- Transport DOT Label:Non-Flammable Gas
- Purity/Quality:
-
99% *data from raw suppliers
HELIUM 95.00% *data from reagent suppliers
Safty Information:
- Pictogram(s):
- Hazard Codes:
- Safety Statements:
9
- MSDS Files:
-
SDS file from LookChem
Total 1 MSDS from other Authors
Useful:
- Chemical Classes:Toxic Gases & Vapors -> Simple Asphyxiants
- Canonical SMILES:[He]
- Recent ClinicalTrials:Helium-Hyperoxia and 6MWT Distance in COPD
- Recent EU Clinical Trials:Prospective randomised cross over comparison on the physiological response to non-invasive ventilation using either Air O2 or Heliox21
- Inhalation Risk:On loss of containment this substance can cause suffocation by lowering the oxygen content of the air in confined areas.
- Effects of Short Term Exposure:The liquid may cause frostbite. Asphyxiation.
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Description
Helium is a colorless, odorless, and tasteless monoatomic gas with
an atomic weight of 4, a density of 1.78 g per 1 at 0°C and 1
atmosphere pressure, and an aqueous solubility of 0.97 mL per
100 mL at 50°C. The Bunsen solubility coefficient (the volume,
in mL, of gas at standard conditions dissolved per mL of liquid).of helium at 38°C is 0.0086 in water, and 0.015 in olive oil. After
hydrogen, helium is the most abundant element in the universe;
these elements are believed to represent 76 and 23 percent, respectively, of all matter in the universe. The earth’s atmosphere, however, contains only 5 ppm of helium. Mineral gases from wells
contain higher concentrations and serve as the principal source for
industrial production. Helium is chemically very inert; it has a
weak tendency to combine with other elements such as fluorine.
It is usually marketed as compressed gas, with the USP grade
containing not less than 99 percent helium.The largest biological use of helium is the replacement for nitrogen
in synthetic breathing gas mixtures for divers and others working
under high pressure conditions. The low solubility in body fluids
compared to nitrogen decreases the danger of bends on depressurizing.
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Physical properties
Helium is a colorless, odorless, and tasteless inert gas that is noncombustible and is the leastsoluble of any gas in water and alcohol. As a gas, it diffuses well in solids. Helium’s freezingpoint is –272.2°C, and its boiling point is –268.93°C. Both temperatures are near absolutezero (–273.13°C, or –459.4°F), where all molecular and thermal motion ceases. Liquid heliumhas the lowest temperature of any known substance. Helium’s density is 0.0001785g/cm3. Helium is the only element that cannot be converted into a solid by lowering the temperature.At normal pressure it remains a liquid at near absolute zero, but if the pressure isincreased, it then turns into a solid.
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Uses
Helium has many uses.
As an inert gas, it is used as the atmosphere in which to “grow” silicon crystals (computerchips).
As a lifting gas, it is used to inflate weather balloons and lighter-than-air ships (blimps)similar to the ones seen taking TV pictures above football games. Even though helium has lesslifting power than hydrogen, it is used for all lighter-than-air ships because it is noncombustibleand thus safer than hydrogen. In addition to blimps, toy balloons are filled with helium.
In arc welding, it is used as an inert gas shield that releases great heat for very long andheavy welds. Helium prevents oxidation of the metal being welded, thus preventing burningand corrosion of the metal. This is one of the major uses of helium.
Helium is used for low-temperature research (–272.2°C or –434°F). It has become importantas a coolant for superconducting electrical systems that, when cooled, offer little resistance to theelectrons passing through a conductor (wire or magnet). When the electrons are “stripped” fromthe helium atom, a positive He++ ion results. The positive helium ions (nuclei) occur in bothnatural and man-made radioactive emissions and are referred to as alpha particles. Helium ions(alpha particles) are used in high-energy physics to study the nature of matter.
In gas discharge lasers, helium transfers the energy to the laser gas such as carbon dioxideor another inert gas;in mixtures with neon and argon for electronic tubes and “neon” signs..
As an inert gas with heat-transfer capability, helium is used in gas-cooled nuclear powerreactors, which operate at a higher efficiency than liquid-cooled nuclear reactors. Theworld’s largest particle accelerators use liquid helium to cool their superconducting magnets.Astronomers use liquid helium to cool their detecting instruments. If this equipment is keptcool, the “thermal noise” produced at higher temperatures is reduced. Gases, diluent. Helium is used as an inert gas shield in arc
welding, as a lifting gas for lighter-than-air aircraft,
and as a gaseous cooling medium in nuclear
reactors. It is also used to provide a protective
atmosphere for growing germanium and
silicon crystals for transistors, to provide a protective
atmosphere in the production of such
reactive metals as titanium and zirconium, to fill
cold-weather fluorescent lamps, to trace leaks in
refrigeration and other closed systems, and to fill neutron and gas thermometers. Its thermal
conductivity makes it an important gas for lasers
and fiber optic production. It is used extensively
in chromatography due to its inertness and high
thermal conductivity. It is used in cryogenic
research such as for superconductivity. In mixtures
with oxygen, it has medical and diving
applications. Radioactive mixtures of helium
with krypton are available to users licensed by
the Nuclear Regulatory Commission. NASA
uses helium for purging and pressurizing the
liquid hydrogen tanks of spacecraft because it is
the only element that remains a gas in the extreme
cold necessary to maintain the liquid hydrogen
fuel used in many rockets and the Space
Shuttle. Liquid helium is used for cooling superconductive
magnets, used in magnetic resonance
imaging, and in magnetic separation.
