Helium
is a chemical element found in nature, which is located at the first
session at the top of Group H in the periodic table of the elements, and
has the symbol "He", which is one of the noble elements inert atomic
number 2, and the advantage of lightly weight, thermal conductivity
high, helium is composed of the nucleus of two protons and two neutrons
in which two, surrounded by two electrons in atomic orbits.
The
helium gas is colorless, odorless and tasteless, non-flammable, devoid
of toxicity, which is the only item that has a speed drop and high
leakage, the chemical activity is very small; because there are two
electrons in the outer Ovlake; any full electronic orbits, making it
stable, so be on a single-atom form, which is slightly soluble in water,
its density and boiling Mnkhvadan also.
The discovery of helium
component for the first time; goes back to 1868, when a total solar
eclipse in India, discovered its existence in the sun before the earth.
The
helium component available in the universe, and also enters in the
composition of the gaseous envelope for many planets, but on the ground
it is rare, is concentrated in the atmosphere by 5.2 ppm, especially in
the upper layers of the atmosphere of it, is due mediocre despite
continuous production him to speed Anflath to outer space. As helium is
produced annually from across the lithosphere Earth 3,000 metric tons,
where large quantities in the installation of metal uranium and thorium
decay because of the radiation, and release alpha particles, which
collects electrons to form helium collide when rock's atmosphere.
There
are several isotopes of helium, which Mstaqran two equals two: Helium
3, which contains a neutron in its nucleus one, and helium-4 that
contains two neutrons in two, which is the natural counterpart to the
most abundant.
The America's largest provider of helium; because
of the discovery of its existence with the natural gas in the ground in
1903 during oil exploration in the state of "Kansas" The US, as the
largest natural source of helium is its presence in the natural gas
wells, as a result stayed away under the rock layers of the Earth, as it
is extracted from there by fractional distillation, but the sources are
running out, and there are small amounts of helium in the mineral
springs, gas eruptions, meteorites, and the crust, as well as in the
waters of the sea, but in spite of the scarcity of the presence of
helium on the ground; it is centered under the Great Plains in large
quantities , as a by-product in the natural gas extraction process.
The
properties characteristic of helium allows use in many areas; it is
used in cooling magnetic devices, and in the manufacture of silicon
wafers and germanium, and is worth mentioning used in the detection of
leaks in machines that use high discharge; because of the spread in
solids faster than the spread in the air, as well as uses helium fill
air ships and balloons to be able to fly; because of the lightness and
the lack of intensity, lack of susceptibility to ignition, unlike
hydrogen, which is characterized by Bkablath of the fires, which was
used in the First World War in the mobilization of airships, and in
military airships processing, also was used in World War II Arc Welding
processes for military equipment, and in the detection of leaks in the
gaseous diffusion process during uranium enrichment; for the manufacture
of the atomic bomb.
This should be careful while using liquid
helium; to lower its temperature as well as the invader; because the
inhalation of helium abundance may be dangerous, as it leads to
suffocation; because it solves needed to replace the process of
breathing oxygen.
Discovery and Etymology
Pierre Jansen
Helium
is the only item that was discovered in the universe and that the sun
before it discovers on the ground. It happened when the astronomer
Pierre Janssen noticed a shiny yellow line in the spectrum version of
the cover of the color of the sun during the incident total solar
eclipse in India in 1868. [5] [6] in the same year the astronomer Joseph
Norman Lockyer noted the same yellow line of the light spectrum of the
sun, and he called Fraunhofer line D3, because it has a wavelength of $
587.49 nm is close to the D1 lines and D2 of sodium. [7] After that, it
concluded Lockyer that the spectral line that caused an element exists
in the sun and does not exist on the ground, fired him along with Edward
Frankland Greek name ἥλιος of the sun Helios. [8] [9] [10]
In
1895, British scientist William Ramsay was able to isolate helium on the
ground, when the treatment of metal Alkljevi (a mineral similar to
Juranini with the presence of about 10% of the rare earth elements) and
that mineral acids. Expect Ramsey presence argon, but after the
separation of nitrogen and oxygen from the liberal gases from the impact
of sulfuric acid, he noticed a distinctive yellow line in the spectrum
of the issuance of the extract, which is similar D3 line in the spectrum
of the sun, and diagnosed these samples as helium by Lockyer and
British physicist William Crookes. [7] [11] [12] [13] In a separate
experiment the world Bear Theodore Klifa with his assistant Abraham
Anglit collect samples of helium gas from metal Alkljevi at Uppsala
University in Sweden in order to determine the atomic mass. [6] [ 14]
[15]
William Ramsey
Scientific discoveries
In 1907,
the world's Ernest Rutherford showed with Thomas Roedz that alpha
particle is the nucleus of helium, through his allowing alpha particles
that penetrate the glass thin tube emptying wall, resulting in a
discharge of the shipment, which allowed studying the spectrum of gas at
home. [16]
Torrent helium for the first time by the physicist
Heike Kamrling ounces in 1908, and it cools the gas to less than a
degree Kelvin one. [17] tried to Owens getting solid state of helium to
reduce the temperature, but it could not do so, because there is no
helium triple point be then the balance between the three cases of the
material. Nevertheless, he was able pupil ounce physicist Hendrik Willem
Kisom of hardener 1 cm 3 of the application of additional pressure
helium at low temperatures and so in 1926. [18]
In 1938, he
discovered that the physicist Pyotr Kapetsa isotope helium-4 almost
colorless viscosity at temperatures close to absolute zero, a phenomenon
known today Balmiuah high. [19] in 1972, observed the same phenomenon
with the isotope helium-3 and that by physicists Ooshirov Douglas and
David Lee and Robert Richardson, and thus have won the Nobel Prize in
Physics in 1996. [20]
Extraction and use
Detected
the presence of helium gas with natural gas in the ground in sufficient
quantities to produce in 1903 during drilling for oil in Dexter in the
state of Kansas, where he collected the amount of gas is flammable. An
analysis of the sample at the University of Kansas process found that
the gas consists of 72% nitrogen and 15% methane and 1% hydrogen and 12%
of the gas did not recognize it then. [6] [21] perform a deeper search
found Hamilton Cady and David McFarland of the University of Kansas that
1.84% of the sample is a helium gas. [22] [23] This research has shown
that despite the scarcity of the presence of helium on the ground it is
centered under the Great Plains in large enough quantities as a
by-product in the natural gas extraction process. [24]
These facts
have made the United States the largest provider of helium, was to take
advantage of that in the First World War in the mobilization of the
Detaining balloons lighter than air gas such as hydrogen, but it is not
flammable. Consequently it has been used helium balloons in military
equipment. The first balloon used for this purpose called US Navy's C-7
and took off the first test flight of its Hampton Roads in Virginia to
Bolling Field military base in Washington in the first of December 1921.
[25] continued to be used helium in the military field until World War
II in Arc Welding processes for military equipment was used as a gas to
detect leaks in the gaseous diffusion process during enrich uranium to
manufacture the atomic bomb in the Manhattan Project. [26]
Natural abundance and production
Natural abundance
Helium constitutes about 19% of the outer atmosphere, the planet Neptune.
Despite
its rarity on the surface of the ground, helium is the second most
elements after hydrogen abundance in the universe, accounting for 23% of
its mass Albarioneh. [6] this huge amount of helium was formed shortly
after the Big Bang. Helium is formed in the stars as a result of nuclear
fusion of hydrogen in proton-proton chain and cycle
carbon-nitrogen-oxygen interaction (CNO) cycle, which is part of the
stellar fusion reactions. [27]
The helium concentration in the
Earth's atmosphere equivalent to 5.2 ppm, which is concentrated in the
upper atmosphere of the Earth's atmosphere. [28] [29] This little focus
relatively constant in the atmosphere, despite continuous production of
helium, it is due to the breakdown of gas from the atmosphere Air ground
to outer space and that several proposed mechanisms. [30] [31]
Helium enters in the composition of the gaseous envelope for many planets rates appear in the following table:
Neptune 19% ± 3.2%
Uranus 15.2% ± 3.3%
Buyer 10.2%
Saturn 3.25%
Venus 12 ppm
Earth 5.2 ppm
Most
of helium on Earth is the result of radioactive decay of heavy elements
as a result of the launch of the alpha particles 2 + He, which collects
electrons to form helium collide when rock's atmosphere. So there is a
relatively large quantities of helium in the installation of several
metals uranium and thorium due to launch the alpha particles during
radioactive decay such as Aljuranini (especially Alkljevi, which is a
derivative Alaoraniti) and Rnoti and monazite. On this basis, about
3,000 metric tons of helium produced annually through the lithosphere.
[32] [33] [34] The helium concentration in the earth's crust is 8 ppb,
and in the sea only about 4 parts per trillion (ppt). There are small
amounts of helium in the mineral springs and volcanic gases and
meteorites.
The biggest natural source of helium is the presence
in some natural gas wells as a result of stayed away under the rock
layers of the Earth. Concentrations vary according to the sites of
several parts per million to about 7% by volume of the amount of
extracted gas as the gas field in San Juan County, New Mexico. [35] [36]
Production
Helium
gas synthetically produced process fractional distillation of natural
gas, which can be found by up to 7% by volume. [37] Since the helium is
less than any chemical element another boiling point, the application of
low temperatures at high pressures lead to monetization of other gases
such as nitrogen and methane. After that purification process for helium
gas successive runs down to low temperatures not take place so as to
ensure the survival of any impact to other gases. A final step of
purification using activated charcoal, which gives the purity of up to
99.995% purity and called Class A. [7] The main impurity in helium Class
A is the neon gas. In the final stage of production of liquefied helium
cooling during operations deep so that it is in the form of liquid
helium, which facilitates the transfer process, as the transfer of a
liquid helium container nine more five times the size that moving
containers helium as a gas. [38] [39]
The United States is the
largest producer of helium gas phase where it came from was producing
more than 90% of the global need for this gas, and the rest is produced
by plants located in Canada, Poland, Russia, in addition to several
other countries. Most of the helium produced in the United States is
from Hogucon gas field in the state of Kansas, as well as other fields
in Oklahoma and in the Panhandle Field in Texas. [38] [40] of helium
large consumption in the United States, and since the early twentieth
century, the United States stock and national of this material. As the
United States consumption of helium gas in 2000, about 15 million kg per
year. [41] in the mid-nineties opened its capacity to produce 17
million cubic meters of helium gas a new plant to generate helium in the
Algerian city of Arzew, which covers the European demand of helium in
the global market . Between 2004 and 2006 two stations for the
production of two new helium and opened in Ras Laffan in Qatar and the
city of Skikda in Algeria. With the opening of Skikda station Algeria
became the second producer of helium in the global market. [38]
According to statistics conducted in 2008, it has extracted about 169
million cubic meters of helium from natural gas and that 78% of the
United States and 10% from Algeria and most of the rest is produced by
multiple countries led by Russia, Poland and Qatar. [42]
The
growing global demand for helium and limited production have led to the
high price of the production of helium in the world, [43] so that
between 2002 and 2007 increased the price of helium twice. [44] as a
result of the limited helium resources are underway to use techniques
where the spread of natural gas, crude apply over half permeable
membranes in order to recover and purify helium. [45]
Isotopes
For more details on this topic, see the helium isotopes.
There
are nine known isotopes of helium, only two of which is a stable
isotope of helium which is -4 4He and helium -3 3He. The isotope
helium-4 is the natural counterpart to the most abundant where that
99.99986% of the helium element in nature is helium-4, and the rest is
helium-3. Statistically there is helium-3 atom and one million compared
to helium-4 atom. [6] produces isotope helium-4 in the ground Knath to
the process of alpha decay of radioactive elements heavier where produce
alpha particles, which are helium nuclei is charged. Featuring Analog
helium-4 nucleus high Bthbatih because Noyatea fully arranged in a
nuclear cover. The quantities of the rare isotope helium-3 found in
nature since the inception of the land, in addition to a decline in
volumes originating from the universe, and that she was held within the
cosmic dust, [46] as small amounts of helium produced from -3 beta decay
of tritium. [47]
Properties isotope 3He 4He
Static energy (MeV) 2809 3728
Density kg / m 3 0.134 0.178
Critical temperature (Kelvin) 3.32 5.20
Lambda point (Kelvin) 0.0025 2.1768
When fusion pressure (MeV) at 0 Kelvin 3.439 2.536
Melting point (Kelvin) 3.19 4.21
The
disparity ratio of two isotopes helium-3 and helium-4 in the rocks used
to determine the age of rocks and find out the origin of origin in the
lithosphere of the Earth. [46] The isotope ratio of helium to the helium
-3 3He -4 4He in the universe higher than on the ground about 100 times
and in the interstellar medium. [48] as that provided in the stars
relatively large as a result of nuclear fusion. The cosmic materials
such as meteorites also contain ratios of helium-3 satellites rock
debris, which had taken her and the solar wind, and the moon's surface
contains helium -3 concentrations higher than on the surface of the
earth. [49] [50]
The combination of equal two quantities of 3He
and 4He liquid under 0.8 Kelvin secede to two layers is Mzojtin as a
result of variation of quantum statistics for them, where that 4He is a
boson, while the 3He fermion. [51] utilized a private non-mixing of
these two isotopes in the refrigerator extension, where you can use this
application to get the temperature up to a few milliseconds Kelvin.
[52]
Physical characteristics [edit]
Helium in quantum mechanics
Representation of a helium atom nucleus appear helium atom in the middle and around the electronic cloud.
From
the perspective of quantum mechanics, the second helium atom can be
made simpler model her after a hydrogen atom. Helium nucleus consisting
of two protons consist of two neutrons and two, surrounded by two
electrons in atomic orbits. According to the traditional Newton
mechanics, it is not possible to provide an analytical mathematical
solution for the system consists of more than two Jsemen, according to
the dilemma of the three objects. Accordingly, mathematical and
numerical methods used by computational chemistry to develop a
quantitative model of the mechanical link electrons helium nucleus.
Despite the simplicity of the nucleus ostensibly form the complex
equations necessary to develop a model to simulate the real corn. [53]
Phases of helium
The
helium normally a gas, and at low temperatures when the melting point
becomes liquid-phase. However, the helium is the only element that can
not get the solid phase of it under normal pressure conditions. Must
raise pressure values up to about 2.5 MPa at very low temperatures
(less than 1.5 Kelvin, equivalent to -272 ° Q). [54]
It is a solid
helium crystals, but can not be separated from the liquid helium steel
visually, because the refractive index very close to them. Helium steel
portability high compression, so it is possible to laboratory size
decrease by more than 30%. [55] of the density of steel helium 0.214 ±
0.006 g / cm 3 at 1.15 K and 66 Joe, expected at 0 Kelvin, density and
pressure of 25 bar is 0.187 ± 0.009 g / cm 3. [56]
The gas phase and the state of the plasma
Helium gas discharge in the form of chemical symbol for the element tube
Be
in helium in the gas phase, in most cases, and that the single-atom gas
and colorless, odorless form. Because of low atomic mass of the helium
conductivity and capacity thermal higher than any other gas except
hydrogen, and the prevalence rate in solids three times higher than the
air and about 65% of the value of hydrogen spread. [7] the helium
refractive index steady compared with other gases so it uses a standard
as to correct errors in the refractive index of the state of gas
measuring devices. [57] at normal temperatures, the helium Jules-Thomson
coefficient negative, which means that it heats up when allowed it to
expand, and only at a temperature reversal temperature ranging between
32 and 50 Kelvin When you press a 1 atmosphere, the helium expands when
cooled. [7] when lower grade helium temperature below this temperature,
the helium can be liquefied by cooling extension.
Most cosmic
helium is in the case of plasma, which have quite different properties
from the atomic helium. In the case of the plasma electrons are not
linked to the nucleus, leading to an increase in electrical
conductivity, even if gas Maana partially. The charged particles are
affected by electric and magnetic fields, and this is what happens to
the particles of helium and hydrogen in the universe in the solar wind
occurs when a mutual effect with the magnetosphere of the Earth, leading
to the formation of currents Birkland and Aurora Borealis. [58]
The liquid phase and high fluidity
Image
of liquid helium, which in the case of high-fluidity helium droplets
attempt to escape from the vessel in which it contains appear.
There are two different situations of helium in the liquid phase Tarafan the status of the case of helium I and helium II.
The case of helium I
When
the helium without boiling point, which amounts to 4.22 kelvin and
above the point lambda amounting to 2.1768 Kelvin, the helium will be in
a liquid state colorless, called the case of helium I. [7] The helium
in its liquid Helium I has a refractive index similar to gas of $ 1.026,
as it has a very low viscosity and density of between 0.145-0.125 g /
ml. [59]
Unlike ordinary liquids, the helium II climbs
on the walls of the container it contains, the phenomenon known as the
layer Rollin.
The case of helium II
When the degree of
liquid helium temperature drops below the lambda point, it begins to
show unusual properties, called this case helium II. When boiling helium
II in which case it is a result of the high thermal conductivity of
bubbles it does not appear, but evaporates directly on the surface. This
situation can be observed in the isotope helium-4 as shown by isotope
helium-3, but a lower temperature than it is for helium-4, not much is
known yet about the properties of helium 3. In case II [7]
It
shows the helium II in case the properties of high fluidity, so that
very low to his wife close to zero. To explain it suggested one theory
the existence of questioners model for Helium II, where liquid helium
without point the author of lambda from a combination of asking, the
first contains a proportion of helium atoms in the ground state and be
in a state of high fluidity and flow without having any viscosity, while
The second section contains a proportion of helium atoms in the excited
state, and acting as a liquid plain his wife. [60]
Of the
characteristics displayed by helium, which in the case of high-fluidity
is climbing property, where the helium which in this case that the leak
and climb the walls of the container it contains until it reaches the
hottest area so it evaporates. It is a high-helium fluidity so thin
layer (chip) thickness of about 30 nm and is called as the chip Rollin
Rollin film, relative to the discoverer Bernard Rollin. [7] [61] [62] as
a result of the properties of Altzlqah this high-fluidity of helium it
is difficult to contain liquid helium.
Chemical properties [edit]
Helium
belongs to a platoon noble gases, which contain two electrons in the
outer valence shell layer, so that the orbits of electronic incomplete
1S2, therefore inert gas, which is less noble gases in terms of chemical
activity after Neon, and therefore the second lowest chemical elements
in terms of chemical activity. [63] helium does not show any chemical
activity under all normal conditions. [55]
Hydride ion helium + HHe.
Be
helium on monatomic form in most cases of material, as it is less a
single-atom solubility of gas (solubility) in water, [64] nor preceded
by weakened solubility in water, but some gases such as quaternary Floro
methane CF4 and sulfur hexafluoride SF6 and eight Floro annular butane
C4F8 which have a solubility (expressed in molar fracture) equivalent to
0.3802 x2 / 10-5 and 0.4394 x2 / 10-5 and 0.2372 x2 / 10-5,
respectively, versus 0.70797 x2 / 10-5 of helium. [65]
Chemical compounds [edit]
The potential for anion structure Florohillat
-OHeF.
No
chemical compounds of helium in the standard conditions of pressure and
temperature, but when the helium exposed to abnormal pressure or as a
result of a letter extrusion of the nucleus of helium circumstances it
can be a chemical compounds unstable known as diodes raised (Axaymr) and
with elements such as tungsten and iodine and fluorine, sulfur,
phosphorus, and so when subject to discharge incandescent or tossing
mail.
Under high vacuum conditions in the mass spectrometer device
can be ion hydride helium is formed, but irremovable. [66] The + HeH in
his ground-stable, but active chemically is very large, so is the
strongest acid according to Bronsted-Lowry where theory that gives the
proton immediately when any contact with the molecule or compound, and
that regardless of focus. Theoretically, can be found there are other
compounds of helium such as Vruhedrid helium HHeF, and that a measure of
a compound Vruhedrid argon. [67] theoretical chemistry calculations
showed the possibility of the presence of other compounds of helium
container on helium-oxygen Association, which can be stable. [68]
The
recent imprisonment of the helium atom inside the carbon cage, so when
you heat the fullerenes to elevated temperatures the presence of helium.
Forming then what is known as fullerenes with the inner surface
endohedral fullerene, which remains containing helium trapped inside
even when a derivation of chemical compounds of them. [69] In the case
of the use of isotope helium-3 can reveal that the use of spectroscopy
nuclear magnetic resonance of helium. [70 ] These vehicles are not
vehicles of helium in the true sense of the word, as there are no signs
of a type of chemical bond between them and the surrounding elements,
but these compounds have properties distinct from the other, and has its
own Stukeomitrih formula. A symbol of these compounds in the following
manner: He @ C60.
Uses
The largest consumption of
helium is used in cooling superconducting magnet devices used in
several techniques such as X MRI, for example.
Helium is used in a
number of areas and applications commensurate with distinctive
properties, such as low boiling point and low density and Anhalalith
point, in addition to the high thermal conductivity and inert
properties. Global production of helium reached in 2008 about 32 million
kg (equivalent to 193 million cubic meters), and was the largest
consumption of him (about 22%) in cooling high-conductivity magnet
devices used in several techniques such as magnetic resonance imaging
machines. [71] The Collider Great hadrons in CERN CERN uses about 96
metric tons of liquid helium to keep temperatures below 1.9 Kelvin. [72]
As
a result of the chemical being idle, helium is used as a gas visor in
the production of silicon chips and germanium in the titanium production
and zirconium in the gaseous chromatography. [55] also uses helium as a
gas visor in arc welding operations on materials that lead welded at
elevated temperatures to Ahaptha or weaken air or nitrogen. [6] The
helium is used instead of argon for welding materials that have a high
thermal conductivity such as aluminum or copper.
Device to detect leaks using helium gas.
From
one of the industrial applications of the helium gas used in the
detection of leaks in machines that use high as containers used in deep
cooling discharge, because helium is spreading in solids three times
faster than air. [73] placed device to detect leaks in it in a room
abandoned from the air and fill helium, helium and measured which are
running from one place using infusion devices dedicated to it. On the
other hand can fill the infusion device to detect the helium and reveals
the place infusion device passes manually on the entire system. [74]
Helium is used to fill balloons
Because
the weight is lighter than air, helium is used to fill air ships and
balloons to be able to fly. Although hydrogen is lighter than helium,
but it is flammable, while the helium does not burn.
Enters the
helium in the installation of breathing gases in deep diving devices,
such as Tramax and Hiluoks, so as to mitigate the anesthetic effects of
greenhouse breathing at high pressures. [75] [76] found that the dive to
depths below 150 meters using breathing oxygen devices-helium lead to
tremor and disorder in sensory motor functions, which is an indication
of the occurrence of the symptoms of high pressure nervous syndrome, or
what is known as tremor helium. [77] This effect can come back to some
extent the result of adding quantities of gas the properties of
anesthetic in diving such as hydrogen or nitrogen to Helium-oxygen
mixture. [78] In such depths, it found that the low density of helium
have a role in easing the effort made to breathe. [79]
