Argon
Argon is a chemical element with the symbol Ar and atomic number 18. It is in Group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in the Earth's atmosphere, at 0.93% (9,300 ppm), making it approximately 23.8 times as abundant as the next most common atmospheric gas, carbon dioxide (390 ppm), and more than 500 times as abundant as the next most common noble gas, neon (18 ppm). Almost all of the argon on Earth is radiogenic argon-40, derived from the decay of potassium-40 in the Earth's crust. In the universe, argon-36 is by far the most common argon isotope, being the one most produced by stellar nucleosynthesis in supernovae.
There are various reasons for using argon in specific applications:
When an inert gas is needed, argon is the most cost-effective alternative, especially when nitrogen is not sufficiently inert.
When low thermal conductivity is required.
When its electronic properties (ionization and/or emission spectrum) are important.
Other noble gases can also be used in such applications, but argon is the cheapest. Argon is not expensive because it occurs naturally in the air and is readily obtained as a byproduct of cryogenic air separation in the production of liquid oxygen and liquid nitrogen: the main components of air are used in large-scale industries. Other noble gases (except helium) are also produced this way, but argon is the most plentiful among them. The scale of argon's applications is significantly increasing because it is inert and relatively inexpensive.
Argon is used in some high-temperature industrial processes. Carbon dioxide is used in the food industry and the oil industry. With the help of carbon dioxide, chemically reactive substances are converted into reactive substances. For example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning.
For some of these processes, the presence of nitrogen and oxygen gases can cause defects within the material. Argon gas is used in different types of electric arc welding methods, such as Gas Metal Arc Welding (GMAW/MIG) and Gas Tungsten Arc Welding (GTAW/TIG), as well as in the processing of titanium and other reactive elements. An argon atmosphere is also used for growing crystals of silicon and germanium.
Argon is used in the poultry industry for mass culling following disease outbreaks, as a more humane method of euthanasia compared to electric water bath stunning. Argon's relatively high density helps maintain the appropriate gas concentration during the gasification period. Its non-reactive nature makes it suitable for use with food products (the poultry), and because it displaces oxygen within the culled bird, argon can also extend shelf life.
Argon is sometimes used in fire suppression to prevent damage to equipment.
Acetylene (systematic name: ethyne) is a chemical compound with the formula C₂H₂.
Argon is a chemical element with the symbol Ar and atomic number 18.
Argon-Carbon Dioxide C-50 (50% argon / 50% CO₂)
Carbon dioxide (chemical formula CO₂)
Helium is a chemical element with the symbol He and atomic number 2.
Nitrogen is a chemical element with the symbol N and atomic number seven.
Oxygen is a chemical element with the symbol O and atomic number 8.
Propane (molecular formula C₃H₈) is an alkane with three carbon atoms.