Download ~The different types of gases~ Oxygen (O2) The most common

~The different types of gases~
Oxygen (O2)
The most common element found in nature is oxygen. One of the major five elements
required to sustain life is oxygen. A tasteless, odourless and colourless gas, oxygen is
essential to life, it is essential for respiration of even plants and animals. It reacts very strongly
in the presence of other chemical substances. By weight, oxygen makes up the following:
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89% of the Earth's water
62% of the human body
46% of the Earth's crust (in the form of silicates, oxides, etc.)
21% of the air we breathe
Nitrogen (N2)
Mainly found in the atmosphere, nitrogen gas makes up 78% of the earth's air, by volume. In
1772 nitrogen was discovered by chemist and physician Daniel Rutherford who showed when
oxygen and carbon dioxide are removed from air, the residual gas, that is nitrogen, would not
support combustion or living organisms. Nitrogen is a neutral and colourless gas. From an
exhaustible source in our atmosphere, including the Earth's crust in the form of nitre, nitrates,
in organic form and also in mineral form, nitrogen gas can be obtained by liquefaction and
fractional distillation. It is found in all living systems as component of the makeup of
biological compounds.
Argon (Ar)
About 0.9% argon exists in the atmosphere. It is a neutral and colourless gas and does not exist in
nature other than in the air. It is a highly useful gas though it cannot sustain life. Argon is soluble in
water in the same amount as oxygen gas and is 2.5 times more soluble in water than nitrogen gas.
Argon gas is used in metals and manufacturing industry, iron and steel industry, laboratories and
semi conductor industry.
Hydrogen (H2)
Hydrogen is only found in the atmosphere at trace levels. But this gas is found in abundant
quantities in hydrocarbons (petroleum and petroleum by-products). It is also found in ordinary water.
Hydrogen constitutes the lightest fraction of the H2O molecule in water. The gas is highly flammable.
A colourless and a very light gas, hydrogen cannot sustain life and reacts easily with other chemical
substances.
Carbon Dioxide (CO2)
This gas is formed from the combination of two elements: oxygen and carbon. Carbon dioxide is
produced from the fermentation of liquids, the combustion of hydrocarbons and the breathing of
humans and animals. Found in small quantities in the atmosphere, it is mixed by plants which in turn
produce oxygen. With a slightly irritating odour, carbon dioxide cannot sustain life. It is colourless
and heavier than air. It forms carbon dioxide snow when it freezes at -78.5 degree C. In an aqueous
solution it forms carbonic acid. In its solid state, CO2 is commonly called dry ice, which is widely used
in the food and beverage industry.
Biogas
Biogas is that type of gas formed by the anaerobic fermentation of biological materials. The
main constituents of biogas are methane and carbon dioxide. Considerable amount of biogas is
produced by sludge digestion in the tanks of sewage treatment plants, which can be referred
to as sewage gas. The anaerobic fermentation of organic residues and agricultural waste and
garbage tips produce biogas, referred to as landfill gas. With no net carbon dioxide emissions
, biomass is a good source of energy to be used as a fuel and can help in reducing the use of
fossil fuels. This in turn can help to reduce the greenhouse effect.
Acetylene (C2H2)
This is not an air gas. This gas is a synthesis gas usually produced from the reaction of calcium
carbide with water. In the 19th century, acetylene was burnt in "acetylene lamps" to light mining
tunnels and homes. Acetylene is a gaseous hydrocarbon. It has a strong garlic odour. The gas is
colourless, unstable, highly combustible. Acetylene produces a very hot flame when combined with
oxygen. Acetylene is used in machine/metal construction for cutting and welding (with oxygen). It is
also used in the glass industry for lubrication of bottle production moulds.
Krypton (Kr), Neon (Ne) and Xenon (Xe)
these gases are known as "rare" gases. They are so called because all the three gases account for
one thousandth of the air which surrounds us. These gases are colourless and tasteless and cannot
sustain life. They are inert gases which do not react. These gases can only be combined with other
chemical substances with great difficulty. This extreme inertness quality in these gases makes them
very valuable for certain applications.
Gaseous Hydrocarbons (CnHm)
The basic characteristic of hydrocarbon gases is that they contain both carbon atoms and
hydrogen atoms. The carbon atoms give the flame its hot colour when burnt and the hydrogen
atoms are particularly combustible. The most well-known gaseous hydrocarbons are as
follows:
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Acetylene (C2H2): The decomposition of calcium carbide in water produces acetylene.
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Methane (CH4): It is main component of natural gas and is also known as "marsh
gas" or "pit gas".
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Ethane (C2H6): This is a petroleum gas. It is used as a fuel.
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Ethylene (C2H4): This is a petroleum gas. It is used to produce many synthetic
products like plastics.
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Propane (C3H8): It is a common petroleum fuel gas. Propane gas is often delivered to
domestic storage tanks.
Butane (C4H10): This is also a petroleum fuel gas. This gas can easily be liquefied. It is sold
in low-pressure cylinders sometimes.
Ozone (03)
this gas is formed by the combination of three oxygen atoms. With a strong and irritating odour, it is
a very unstable gas. This gas is corrosive, very toxic. It is also a strong oxidant. It is therefore
absolutely unsuitable to sustain life. This gas is produced by generating high-power electrical
discharges in the air or in oxygen. Ozone gas is found in the upper layers of the atmosphere. The gas
serves as a shield which protects the earth from the sun's ultraviolet radiation. The gas is used to
sterilize water, bleach textiles, neutralize odours, paper, and in certain chemical manufacturing
processes.