Information AboutCarbon Dioxide |
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Carbon dioxide is a Chemical Compound composed of two Oxygen Atom s Covalently Bonded to a single Carbon atom. It is a gas at Standard Temperature And Pressure and exists in Earth's Atmosphere as a gas. It is currently at a globally averaged Concentration of approximately 385 Ppm by Volume in the Earth's atmosphere, although this varies both by location and time. Carbon dioxide's Chemical Formula is . In general, it is exhaled by animals and utilized by plants during Photosynthesis . Additional carbon dioxide is created by the Combustion of Fossil Fuels or vegetable matter, among other chemical processes. Carbon dioxide is an important Greenhouse Gas because of its ability to absorb many Infrared Wavelengths of the Sun 's light, and because of the length of time it stays in the Earth's atmosphere. Due to this, and the role it plays in the Respiration of plants, it is a major component of the Carbon Cycle . In its solid state, carbon dioxide is commonly called Dry Ice . Carbon dioxide has no liquid state at pressures below 5.1 Atm . CHEMICAL AND PHYSICAL PROPERTIES Carbon dioxide is a colorless, odorless gas. When inhaled at concentrations higher than usual atmospheric levels, it can produce a sour taste in the mouth and a stinging sensation in the nose and throat. These effects result from the gas dissolving in the Mucous Membranes and Saliva , forming a weak solution of Carbonic Acid . This sensation can also occur during an attempt to stifle a burp after drinking a Carbonated Beverage . Amounts above 800 ppm are considered unhealthy, amounts above 5,000 ppm are considered very unhealthy, and those above about 50,000 ppm are considered dangerous to animal life.1 At Standard Temperature And Pressure , the density of carbon dioxide is around 1.98 kg/m³, about 1.5 times that of Air . The carbon dioxide molecule (O=C=O) contains two Double Bonds and has a linear shape. It has no electrical Dipole , and as it is fully Oxidized , it is not very Reactive and is non-flammable. At −78.5° C , carbon dioxide changes directly from a solid phase to a gaseous phase through Sublimation , or from gaseous to solid through Deposition . Solid carbon dioxide is normally called " Dry Ice ", a Generic Trademark . It was first observed in 1825 by the French chemist Charles Thilorier . Dry ice is commonly used as a versatile cooling agent, and it is relatively inexpensive. As it warms, solid carbon dioxide sublimes directly into the gas phase, making its use convenient as it leaves no liquid. It can often be found in groceries and laboratories, and it is also used in the shipping industry. The largest non-cooling use for dry ice is blast cleaning. Liquid carbon dioxide forms only at Pressure s above 5.1 atm; the Triple Point of carbon dioxide is about 518 KPa at −56.6°C (See phase diagram, above). The Critical Point is 7,821 kPa at 31.1°C. An alternative form of solid carbon dioxide, an Amorphous glass-like form, is possible, although not at atmospheric pressure.2 This form of glass, called ''carbonia'' , was produced by Supercooling heated at extreme pressure (40–48 GPa or about 400,000 atmospheres) in a Diamond Anvil . This discovery confirmed the theory that carbon dioxide could exist in a glass state similar to other members of its elemental family, like Silicon ( Silica Glass ) and Germanium . Unlike silica and germania glasses, however, carbonia glass is not stable at normal pressures and reverts back to gas when pressure is released. See Also: Supercritical carbon dioxide dry ice HISTORY OF HUMAN UNDERSTANDING Carbon dioxide was one of the first gases to be described as a substance distinct from air. In the seventeenth century, the Flemish chemist Jan Baptist Van Helmont observed that when he burned Charcoal in a closed vessel, the mass of the resulting ash was much less than that of the original charcoal. His interpretation was that the rest of the charcoal had been transmuted into an invisible substance he termed a "gas" or "wild spirit" (''spiritus sylvestre''). The properties of carbon dioxide were studied more thoroughly in the 1750s by the Scottish physician Joseph Black . He found that Limestone ( Calcium Carbonate ) could be heated or treated with Acid s to yield a gas he called "fixed air." He observed that the fixed air was denser than air and did not support either flame or animal life. He also found that when bubbled through an aqueous solution of lime ( Calcium Hydroxide ), it would Precipitate calcium carbonate. He used this phenomenon to illustrate that carbon dioxide is produced by animal respiration and microbial fermentation. In 1772, English chemist Joseph Priestley published a paper entitled ''Impregnating Water with Fixed Air'' in which he described a process of dripping Sulfuric Acid (or ''oil of vitriol'' as Priestley knew it) on chalk in order to produce carbon dioxide, and forcing the gas to dissolve by agitating a bowl of water in contact with the gas.3 Carbon dioxide was first liquefied (at elevated pressures) in 1823 by Humphry Davy and Michael Faraday .4 The earliest description of solid carbon dioxide was given by Charles Thilorier , who in 1834 opened a pressurized container of liquid carbon dioxide, only to find that the cooling produced by the rapid evaporation of the liquid yielded a "snow" of solid .5 ISOLATION Carbon dioxide may be obtained from air Distillation . However, this yields only very small quantities of . A large variety of chemical reactions yield carbon dioxide, such as the reaction between most acids and most metal carbonates. For example, the reaction between Sulfuric Acid and calcium carbonate (limestone or chalk) is depicted below: : The then decomposes to water and . Such reactions are accompanied by foaming or bubbling, or both. In industry such reactions are widespread because they can be used to neutralize waste acid streams. The production of Quicklime (CaO) a chemical that has widespread use, from limestone by heating at about 850 °C also produces : : The Combustion of all carbon containing fuels, such as Methane ( Natural Gas ), petroleum distillates ( Gasoline , Diesel , Kerosene , Propane ), but also of coal and wood, will yield carbon dioxide and, in most cases, water. As an example the chemical reaction between methane and oxygen is given below. : Iron is reduced from its oxides with Coke in a Blast Furnace , producing Pig Iron and carbon dioxide: : Yeast produces carbon dioxide and Ethanol , also known as alcohol, in the production of wines, beers and other spirits: : Glucose → All Aerobic organisms produce when they oxidize Carbohydrate s, Fatty Acid s, and proteins in the mitochondria of cells. is the prime energy source and the main Metabolic pathway in Heterotroph organisms such as animals, and also a secondary energy source in Phototroph organisms such as plants when not enough light is available for Photosynthesis . The large number of reactions involved are exceedingly complex and not described easily. Refer to ( Cellular Respiration , Anaerobic Respiration and Photosynthesis ). Photoautotrophs (i.e. plants, Cyanobacteria ) use another ''modus operandi'': They absorb the from the air, and, together with water, react it to form carbohydrates: : Carbon dioxide is Soluble in water, in which it spontaneously interconverts between and ( Carbonic Acid ). The relative concentrations of , and the deprotonated forms ( Bicarbonate ) and ( Carbonate ) depend on the PH . In neutral or slightly alkaline water (pH > 6.5), the bicarbonate form predominates (>50%) becoming the most prevalent (>95%) at the pH of seawater, while in very alkaline water (pH > 10.4) the predominant (>50%) form is carbonate. The bicarbonate and carbonate forms are very soluble, such that air-equilibrated ocean water (mildly alkaline with typical pH = 8.2 – 8.5) contains about 120 mg of bicarbonate per liter. Industrial production Carbon dioxide is manufactured mainly from six processes:6 # As a byproduct in ammonia and hydrogen plants, where methane is converted to ; # From combustion of carbonaceous fuels; # As a byproduct of Fermentation ; # From thermal decomposition of ; # As a byproduct of Sodium Phosphate manufacture; # Directly from natural carbon dioxide gas wells. USES Carbon dioxide is used by the food industry, the oil industry, and the chemical industry. It is used in many consumer products that require pressurized gas, because is inexpensive, nonflammable, and it undergoes a phase transition from gas to liquid at room temperature at an attainable pressure of approximately 60 Bar , allowing far more carbon dioxide to fit in a given container than otherwise would. Life jackets often contain canisters of pressured carbon dioxide for quick inflation. Aluminum capsules are also sold as supplies of compressed gas for Airguns , Paintball markers, for inflating bicycle tires, and for making Seltzer . Rapid vaporization of liquid is used for blasting in coal mines. Carbon dioxide is used to produce Carbonated Soft Drink s and Soda Water . Traditionally, the carbonation in beer and sparkling wine comes about through natural fermentation, but some manufacturers carbonate these drinks artificially. A candy called Pop Rocks is pressurized with carbon dioxide gas at about 40 bar (600 psi). When placed in the mouth, it dissolves (just like other hard candy) and releases the gas bubbles with an audible "pop." Leavening Agent s produce carbon dioxide to cause dough to rise. Baker's Yeast produces carbon dioxide by fermentation within the dough, while chemical leaveners such as Baking Powder and Baking Soda release carbon dioxide when heated or if exposed to Acid s. .]] Carbon dioxide is the most commonly used compressed gas for pneumatic systems in Combat Robots . Carbon dioxide extinguishes flames, and some Fire Extinguishers , especially those designed for electrical fires, contain liquid carbon dioxide under pressure. Carbon dioxide also finds use as an atmosphere for Welding , although in the welding arc, it reacts to Oxidize most metals. Use in the automotive industry is common despite significant evidence that welds made in carbon dioxide are Brittle r than those made in more inert atmospheres, and that such weld joints deteriorate over time because of the formation of carbonic acid. It is used as a welding gas primarily because it is much less expensive than more inert gases such as Argon or Helium . Liquid carbon dioxide is a good Solvent for many Organic Compounds , and is used to remove caffeine from coffee. First, the green coffee beans are soaked in water. The beans are placed in the top of a column seventy feet (21 meters) high. The carbon dioxide fluid at about 93 degrees Celsius enters at the bottom of the column. The caffeine diffuses out of the beans and into the carbon dioxide. Carbon dioxide has begun to attract attention in the Pharmaceutical and other chemical processing industries as a less toxic alternative to more traditional solvents such as Organochloride s. It's used by some Dry Cleaners for this reason. (See Green Chemistry .) Plants require carbon dioxide to conduct Photosynthesis , and greenhouses may enrich their atmospheres with additional to boost plant growth. It has been proposed that carbon dioxide from power generation be bubbled into ponds to grow algae that could then be converted into Biodiesel fuel {Link without Title} . High levels of carbon dioxide in the atmosphere effectively exterminate many pests. Greenhouses will raise the level of to 10,000 ppm (1%) for several hours to eliminate pests such as whiteflies, spider mites, and others. In medicine, up to 5% carbon dioxide is added to pure Oxygen for stimulation of breathing after Apnea and to stabilize the balance in blood. A common type of industrial gas Laser is the Carbon Dioxide Laser . Carbon dioxide can also be combined with Limonene oxide from orange peels or other Epoxides to create polymers and plastics7. Carbon dioxide is commonly injected into or adjacent to producing oil wells. It acts as both a pressurizing agent and, when dissolved into the underground Crude Oil , significantly reduces its viscosity, enabling the oil to flow more rapidly through the earth to the removal well. In mature oil fields, extensive pipe networks are used to carry the carbon dioxide to the injection points. In the chemical industry, carbon dioxide is used for the production of Urea , Carbonate s and Bicarbonate s, and Sodium Salicylate . Liquid and solid carbon dioxide are important Refrigerant s, especially in the food industry, where they are employed during the transportation and storage of ice cream and other frozen foods. Solid carbon dioxide is called "dry ice" and is used for small shipments where refrigeration equipment is not practical. Liquid carbon dioxide (industry nomenclature R744 / R-744) was used as a refrigerant prior to the discovery of 8 is interested in CO2 Technology. By end-2007, the global car industry is expected to decide on the next-generation refrigerant in car air conditioning. is one discussed option.(see The Cool War ) IN THE EARTH'S ATMOSPHERE .]] Carbon dioxide in Earth's Atmosphere is considered a trace gas, and is measured in parts per million. Current concentration levels average approximately 385 Ppm , which represents a total of around 800 gigatons of carbon. Its concentration can vary considerably on a regional basis: in urban areas and it is generally considerably higher, and indoors can reach over 100 times the atmospheric concentration. Carbon dioxide is a Greenhouse Gas ; see Greenhouse Effect for more. Due to human activities such as the combustion of Fossil Fuels and Deforestation , the concentration of atmospheric carbon dioxide has increased by about 35% since the beginning of the industrialization. |
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