Carbon dioxide
IUPAC name	Carbon dioxide
Other names	Carbonic acid gas; carbonic anhydride; dry ice (solid)
Identifiers
CAS number	[124-38-9]
PubChem	280
EINECS number	204-696-9
RTECS number	FF6400000
SMILES	C(=O)=O
InChI	1/CO2/c2-1-3
Properties
Molecular formula	CO2
Molar mass	44. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general Dry ice is solid Carbon dioxide. It is commonly used as a versatile cooling agent CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to PubChem is a Database of chemical Molecules The system is maintained by the National Center for Biotechnology Information (NCBI a component The EINECS number (for European Inventory of Existing Chemical Substances) is a registry number given to each Chemical substance commercially available in the Registry of Toxic Effects of Chemical Substances ( RTECS) is a Database of Toxicity information compiled from the open scientific literature without reference The IUPAC International Chemical Identifier ( InChI, pronounced "INchee" is a textual Identifier for Chemical substances designed to provide a A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 0095(14) g/mol
Appearance	colorless gas
Density	1,600 g/L, solid; 1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 98 g/L, gas
Melting point	−57 °C (216 K) (under pressure)
Boiling point	−78 °C (195 K), (sublimes)
Solubility in water	1. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid Sublimation of an element or compound is a transition from the Solid to Gas phase with no intermediate liquid stage Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Water is a common Chemical substance that is essential for the survival of all known forms of Life. 45 g/L
Acidity (pKa)	6. 35 and 10. 33
Viscosity	0. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. 07 cP at −78 °C
Dipole moment	zero
Structure
Molecular shape	linear
Related compounds
Related oxides	carbon monoxide; carbon suboxide; dicarbon monoxide; carbon trioxide
Supplementary data page
Structure and properties	n, εr, etc. The poise (symbol P pwɑːz is the unit of dynamic Viscosity in the Centimetre gram second system of units. In physics there are two kinds of dipoles ( Hellènic: di(s- = two- and pòla = pivot hinge An electric dipole is a Molecular geometry or molecular structure is the three- Dimensional arrangement of the Atoms that constitute a Molecule. In Chemistry, the Linear Molecular geometry describes the arrangement of three or more atoms placed at an expected bond angle of 180º An oxide is a Chemical compound containing at least one Oxygen atom as well as at least one other element Carbon monoxide, with the chemical formula CO is a colorless odorless tasteless yet highly toxic Gas. Carbon suboxide, or tricarbon dioxide C3O2with four cumulative double bonds making it a Cumulene. Dicarbon Monoxide (C2O is an extremely reactive Molecule that contains two Carbon Atoms and one Oxygen and save the page -->This page provides supplementary chemical data on Carbon dioxide. and save the page -->This page provides supplementary chemical data on Carbon dioxide. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium Measurement The relative static permittivity εr can be measured for static Electric fields as follows first the Capacitance of a test
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Carbon dioxide (chemical formula: CO₂) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. and save the page -->This page provides supplementary chemical data on Carbon dioxide. and save the page -->This page provides supplementary chemical data on Carbon dioxide. Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry ( UV/ VIS) involves the Spectroscopy of Photons in the UV-visible Infrared spectroscopy (IR spectroscopy is the subset of Spectroscopy that deals with the Infrared region of the Electromagnetic spectrum. Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is the name given to a technique which exploits the magnetic properties of certain nuclei Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state. This page is about the physical properties of gas as a state of matter In Physical sciences standard conditions for temperature and pressure are Standard sets of conditions for experimental measurements to allow comparisons to be made Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five It is currently at a globally averaged concentration of approximately 387 ppm by volume in the Earth's atmosphere,^[1] although this varies both by location and time. "Parts-per" notation is used especially in Science and Engineering, to denote Ratios (relative proportions in measured quantities particularly The volume of any solid plasma vacuum or theoretical object is how much three- Dimensional space it occupies often quantified numerically Carbon dioxide is an important greenhouse gas because it transmits visible light but absorbs strongly in the infrared and near-infrared. Greenhouse gases are gaseous constituents of the atmosphere bothnatural and anthropogenic that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of

Carbon dioxide is produced by all animals, plants, fungi and microorganisms during respiration and is used by plants during photosynthesis. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. This is to make sugars which may either be consumed again in respiration or used as the raw material for plant growth. It is, therefore, a major component of the carbon cycle. The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the Biosphere, Pedosphere, Geosphere, Hydrosphere, and Carbon dioxide is generated as a byproduct of the combustion of fossil fuels or vegetable matter, among other chemical processes. Fossil fuels or mineral fuels are fossil source Fuels that is Hydrocarbons found within the top layer of the Earth’s crust. Some carbon dioxide is output by volcanoes and other geothermal processes such as hot springs. Plate tectonics and hotspots Divergent plate boundaries At the A hot spring is a spring that is produced by the emergence of geothermally heated Groundwater from the earth's crust.

Carbon dioxide has no liquid state at pressures below 5. 1 atm, but is a solid at temperatures below -78 °C. The Standard atmosphere is an international reference pressure defined as 101325 Pa and formerly used as unit of Pressure (symbol atm In its solid state, carbon dioxide is commonly called dry ice. Dry ice is solid Carbon dioxide. It is commonly used as a versatile cooling agent

CO₂ is an acidic oxide: an aqueous solution turns litmus from blue to pink. An acidic oxide (sometimes known as an acidic anhydride, but not to be confused with an Acid anhydride) is an Oxide that either reacts with Litmus is a Water - Soluble mixture of different Dyes Extracted from Lichens, especially Roccella tinctoria.

CO₂ is toxic in higher concentrations: 1% (10,000 ppm) will make some people feel drowsy, whereas 5% is directly toxic.

Contents 1 Chemical and physical properties 2 History of human understanding 3 Isolation 3.1 Industrial production 4 Uses 5 In the Earth's atmosphere 6 In the oceans 7 Biological role 7.1 Role in photosynthesis 7.2 Toxicity 7.3 Human physiology 8 See also 9 References 10 External links

Chemical and physical properties

For more details on this topic, see Carbon dioxide (data page). In Thermodynamics, the triple point of a substance is the Temperature and Pressure at which three phases (for example Gas, Liquid and save the page -->This page provides supplementary chemical data on Carbon dioxide.

Carbon dioxide is a colorless, odorless gas. When inhaled at concentrations much 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. The mucous membranes (or mucosae; singular mucosa) are linings of mostly endodermal origin covered in Epithelium, which are involved in For the band see Saliva (band; for the village in Azerbaijan see Səliva. Carbonic acid (ancient name acid of air or aerial acid) has the formula H2CO3 This sensation can also occur during an attempt to stifle a burp after drinking a carbonated beverage. Amounts above 5,000 ppm are considered very unhealthy, and those above about 50,000 ppm (equal to 5% by volume) are considered dangerous to animal life. ^[2]

At standard temperature and pressure, the density of carbon dioxide is around 1. In Physical sciences standard conditions for temperature and pressure are Standard sets of conditions for experimental measurements to allow comparisons to be made 98 kg/m³, about 1. 5 times that of air. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five 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 moderately reactive and is non-flammable, but will support the combustion of metals such as magnesium. In physics there are two kinds of dipoles ( Hellènic: di(s- = two- and pòla = pivot hinge An electric dipole is a Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24

Small pellets of dry ice subliming in air.

Crystal structure of dry ice

At −78. 51° C or -109. The Celsius Temperature scale was previously known as the centigrade scale. 3° F, carbon dioxide changes directly from a solid phase to a gaseous phase through sublimation, or from gaseous to solid through deposition. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 Sublimation of an element or compound is a transition from the Solid to Gas phase with no intermediate liquid stage In Chemistry, deposition is the settling of particles ( Atoms or Molecules or Sediment from a Solution, suspension and mixture Solid carbon dioxide is normally called "dry ice", a generic trademark. Dry ice is solid Carbon dioxide. It is commonly used as a versatile cooling agent A genericized trademark (also known as a generic trademark or proprietary eponym) is a Trademark or Brand name that has become the colloquial It was first observed in 1825 by the French chemist Charles Thilorier. Charles Thilorier was a Scientist who gave the earliest description of solid Carbon dioxide. Dry ice is commonly used as a cooling agent, and it is relatively inexpensive. A convenient property for this purpose is that solid carbon dioxide sublimes directly into the gas phase leaving no liquid. It can often be found in grocery stores and laboratories, and it is also used in the shipping industry. The largest non-cooling use for dry ice is blast cleaning. Dry ice blasting is a process in which Dry ice is accelerated in a pressurized air stream and directed at a surface in order to clean it

Liquid carbon dioxide forms only at pressures above 5. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface 1 atm; the triple point of carbon dioxide is about 518 kPa at −56. In Thermodynamics, the triple point of a substance is the Temperature and Pressure at which three phases (for example Gas, Liquid 6 °C (See phase diagram, above). The critical point is 7. In Physical chemistry, Thermodynamics, Chemistry and Condensed matter physics, a critical point, also called a critical state 38 MPa at 31. 1 °C. ^[3]

An alternative form of solid carbon dioxide, an amorphous glass-like form, is possible, although not at atmospheric pressure. An amorphous solid is a Solid in which there is no Long-range order of the positions of the Atoms (Solids in which there is long-range atomic order are ^[4] This form of glass, called carbonia, was produced by supercooling heated CO₂ at extreme pressure (40–48 GPa or about 400,000 atmospheres) in a diamond anvil. Amorphous carbonia, also called a-carbonia or a-CO2, is an exotic amorphous solid form of Carbon dioxide that is analogous to amorphous A diamond anvil cell (DAC consists of two opposing Diamonds with a sample compressed between the Culets Extreme pressure, which can exceed 1000000 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. Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide Germanium (dʒɚˈmeɪniəm is a Chemical element with the symbol Ge and Atomic number 32 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 and dry ice

History of human understanding

Carbon dioxide was one of the first gases to be described as a substance distinct from air. The nature of super critical carbon dioxide is established as a solvent for use in extraction Dry ice is solid Carbon dioxide. It is commonly used as a versatile cooling agent 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. The terms Fleming and Flemings ( Vlaming and Vlamingen in Dutch) denote respectively a person and people and the Flemings or Jan Baptist van Helmont (bapt January 12, 1579 &ndash December 30, 1644) was an Early modern period Flemish Charcoal' is the blackish residue consisting of impure Carbon obtained by removing water and other volatile constituents from Animal and Vegetation 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. Joseph Black ( April 16, 1728 &ndash December 6, 1799) was a Scottish Physicist and Chemist, known for his He found that limestone (calcium carbonate) could be heated or treated with acids to yield a gas he called "fixed air. Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are " 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. Calcium hydroxide, traditionally called slaked lime, hydrated lime, or pickling lime, is a Chemical compound with the chemical formula Precipitation is the formation of a Solid in a Solution during a Chemical reaction. 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. Joseph Priestley (13 March 1733 ( Old Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. ^[5]

Carbon dioxide was first liquefied (at elevated pressures) in 1823 by Humphry Davy and Michael Faraday. Sir Humphry Davy 1st Baronet FRS MRIA (17 December 1778 &ndash 29 May 1829 was a British Chemist and inventor Michael Faraday, FRS ( September 22 1791 – August 25 1867) was an English ^[6] 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 CO₂. Charles Thilorier was a Scientist who gave the earliest description of solid Carbon dioxide. ^[7]

Isolation

Carbon dioxide may be obtained from air distillation. Distillation is a method of separating Mixtures based on differences in their volatilities in a boiling liquid mixture However, this yields only very small quantities of CO₂. 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:

H₂SO₄ + CaCO₃ → CaSO₄ + H₂CO₃

The H₂CO₃ then decomposes to water and CO₂. Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. 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 CO₂:

CaCO₃ → CaO + CO₂

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. Calcium oxide ( CaO) commonly known as burnt lime, lime or quicklime, is a widely used Chemical compound. Combustion or burning is a complex sequence of Exothermic chemical reactions between a Fuel and an Oxidant accompanied by the production of Methane is a Chemical compound with the molecular formula. It is the simplest Alkane, and the principal component of Natural gas. Natural gas is a Gaseous Fossil fuel consisting primarily of Methane but including significant quantities of Ethane, Propane, Diesel or Diesel fuel (ˈdiːzəl in general is any Fuel used in Diesel engines The most common is a specific fractional distillate of petroleum Kerosene, sometimes spelled kerosine in scientific and industrial usage is a Combustible Hydrocarbon liquid Propane is a three- Carbon Alkane, normally a gas but compressible to a liquid that is transportable As an example the chemical reaction between methane and oxygen is given below.

CH₄ + 2 O₂ → CO₂ + 2 H₂O

Iron is reduced from its oxides with coke in a blast furnace, producing pig iron and carbon dioxide:

2 Fe₂O₃ + 3 C → 4 Fe + 3 CO₂

Yeast metabolizes sugar to produce carbon dioxide and ethanol, also known as alcohol, in the production of wines, beers and other spirits:

C₆H₁₂O₆ → 2 CO₂ + 2 C₂H₅OH

All aerobic organisms produce CO₂ when they oxidize carbohydrates, fatty acids, and proteins in the mitochondria of cells. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Coke is a solid Carbonaceous material derived from Destructive distillation of low-ash low-sulfur Bituminous coal. A blast furnace is a type of metallurgical Furnace used for Smelting to produce metals generally Iron. Pig iron is the intermediate product of Smelting Iron ore with coke, usually with Limestone as a flux Yeasts are a growth form of eukaryotic Microorganisms classified in the kingdom Fungi, with about 1500 Species currently described Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. Cellular respiration is the set of the metabolic reactions and processes that take place in Organisms cells to convert biochemical energy from Carbohydrates (from ' Hydrates of Carbon ' or saccharides ( Greek σάκχαρον meaning " Sugar " are the most In Chemistry, especially Biochemistry, a fatty acid is a Carboxylic acid often with a long unbranched Aliphatic tail ( chain) which The large number of reactions involved are exceedingly complex and not described easily. Refer to (cellular respiration, anaerobic respiration and photosynthesis). Cellular respiration is the set of the metabolic reactions and processes that take place in Organisms cells to convert biochemical energy from See also Fermentation (biochemistry Anaerobic respiration (anaerobiosis refers to the Oxidation of molecules in the absence of Oxygen to produce Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. Photoautotrophs (i. Photoautotrophs or Phototroph ( Gk: photo = light auto = self troph = nourishment are Organisms (commonly plants that carry out Photosynthesis e. plants, cyanobacteria) use another modus operandi: Plants absorb CO₂ from the air, and, together with water, react it to form carbohydrates:

nCO₂ + nH₂O → (CH₂O)_n + nO₂

Carbon dioxide is soluble in water, in which it spontaneously interconverts between CO₂ and H₂CO₃ (carbonic acid). Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Carbonic acid (ancient name acid of air or aerial acid) has the formula H2CO3 The relative concentrations of CO₂, H₂CO₃, and the deprotonated forms HCO₃⁻ (bicarbonate) and CO₃²⁻(carbonate) depend on the pH. In Inorganic chemistry, bicarbonate ( IUPAC -recommended nomenclature hydrogencarbonate) is an intermediate form in the Deprotonation In Chemistry, a carbonate is a salt or Ester of Carbonic acid. pH is the measure of the acidity or alkalinity of a Solution. 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:^[8]

1. As a byproduct in ammonia and hydrogen plants, where methane is converted to CO₂;
2. From combustion of wood and fossil fuels;
3. As a byproduct of fermentation of sugar in the brewing of beer, whisky and other alcoholic beverages;
4. From thermal decomposition of limestone, CaCO₃, in the manufacture of lime, CaO;
5. As a byproduct of sodium phosphate manufacture;
6. Directly from natural carbon dioxide springs, where it is produced by the action of acidified water on limestone or dolomite. Wood is hard fibrous lignified structural tissue produced as secondary Xylem in the stems of Woody plants notably trees but also shrubs Fossil fuels or mineral fuels are fossil source Fuels that is Hydrocarbons found within the top layer of the Earth’s crust. Fermentation is the process of deriving energy from the oxidation of organic compounds such as carbohydrates using an endogenous electron acceptor which is Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. Brewing is the production of Alcoholic beverage and Alcohol fuel through fermentation. Beer is the world's oldest and most widely consumed Alcoholic beverage and the third most popular drink overall after water and tea Whisky (uisge-beatha or whiskey (uisce beatha or fuisce) refers to a broad category of Alcoholic beverages that are distilled from fermented In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon A drink, or beverage, is a Liquid specifically prepared for Human consumption Sodium phosphate is a generic term for the salts of Sodium and Phosphate. A spring is a point where Groundwater flows out of the ground and is thus where the Aquifer surface meets the ground surface Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Dolomite (ˈdɒləmaɪt is the name of a Sedimentary Carbonate rock and a Mineral, both composed

Uses

Carbon dioxide is used by the food industry, the oil industry, and the chemical industry. ^[8] It is used in many consumer products that require pressurized gas because it is inexpensive and nonflammable, and because it undergoes a phase transition from gas to liquid at room temperature at an attainable pressure of approximately 60 bar (870 psi, 59 atm), allowing far more carbon dioxide to fit in a given container than otherwise would. The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure. 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. "Air rifle" and "Air pistol" redirect here For other uses see Air gun (disambiguation An air gun ( air rifle Paintball is a sport in which players eliminate opponents from play by hitting them with dye-filled breakable oil and gelatin paintballs usually shot from a carbon dioxide or compressed-gas Rapid vaporization of liquid carbon dioxide is used for blasting in coal mines. High concentrations of carbon dioxide can also be used to kill pests, such as the Common Clothes Moth. "Carpet moth" redirects here This term is also used for several Geometer moths of the Subfamily Larentiinae called "carpets"

Carbon dioxide is used to produce carbonated soft drinks and soda water. Soft drink is a beverage that does not contain Alcohol. Carbonated soft drinks are commonly known as soda soda pop pop, or 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). For the music see Pop rock. Pop Rocks (referred to in the United Kingdom as Space dust) is a carbonated Candy with ingredients When placed in the mouth, it dissolves (just like other hard candy) and releases the gas bubbles with an audible pop.

Leavening agents produce carbon dioxide to cause dough to rise. A leavening agent (sometimes called just leavening or leaven) is a substance used in Doughs and batters that causes a foaming action intended Baker's yeast produces carbon dioxide by fermentation of sugars within the dough, while chemical leaveners such as baking powder and baking soda release carbon dioxide when heated or if exposed to acids. Baker's yeast is the common name for the strains of Yeast commonly used as a Leavening agent in Baking Bread and related products where it converts Baking powder is a dry chemical Leavening agent used in cooking mainly baking Sodium bicarbonate or sodium hydrogen carbonate is the Chemical compound with the formula NaHCO3 In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are

Carbon dioxide is the most commonly used compressed gas for pneumatic systems in portable pressure tools and combat robots. Robot Combat is a Hobby / Sport in which two or more Radio-controlled machines use varied methods of destroying or disabling the other Robot

Carbon dioxide extinguishes flames, and some fire extinguishers, especially those designed for electrical fires, contain liquid carbon dioxide under pressure. A fire extinguisher is an Active fire protection device used to extinguish or control small fires often in emergency situations Carbon dioxide also finds use as an atmosphere for welding, although in the welding arc, it reacts to oxidize most metals. Welding is a fabrication process that joins materials usually Metals or Thermoplastics by causing coalescence. Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state Use in the automotive industry is common despite significant evidence that welds made in carbon dioxide are brittler 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. This article pertains to the chemical element For other uses see Argon (disambiguation. Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical

Liquid carbon dioxide is a good solvent for many lipophilic organic compounds, and is used to remove caffeine from coffee. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. Lipophilicity, fat-liking, refers to the ability of a Chemical compound to dissolve in fats oils lipids and non-polar solvents such as Hexane or Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation Caffeine is a bitter white crystalline Xanthine Alkaloid that acts as a Psychoactive Stimulant Drug and a mild Diuretic CoFFEE is an Open source Software for computer supported collaborative learning (CSCL in a digital classroom 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 organochlorides. Applications The simplest form of organochlorides are chlorinated Hydrocarbons These consist of simple Hydrocarbons in which one or more hydrogen atoms have It's used by some dry cleaners for this reason. Dry cleaning is any cleaning process for Clothing and Textiles using an organic Solvent rather than Water. (See green chemistry. Green chemistry, also called sustainable chemistry is a chemical philosophy encouraging the design of products and processes that reduce or eliminate the use and generation of hazardous )

Plants require carbon dioxide to conduct photosynthesis, and greenhouses may enrich their atmospheres with additional CO₂ to boost plant growth, since its low present-day atmosphere concentration is just above the "suffocation" level for green plants. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. A photosynthesis-related drop in carbon dioxide concentration in a greenhouse compartment can kill green plants. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. At high concentrations, carbon dioxide is toxic to animal life, so raising the concentration to 10,000 ppm (1%) for several hours can eliminate pests such as whiteflies and spider mites in a greenhouse. The whiteflies, comprising only the family Aleyrodidae, are small Homopterans More than 1550 species have been described Spider mites are members of the Acari (mite family Tetranychidae, which includes about 1600 species

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. Biodiesel refers to a non-petroleum-based Diesel fuel consisting of short chain Alkyl ( Methyl or ethyl) Esters made by ^[9] In medicine, up to 5% carbon dioxide is added to pure oxygen for stimulation of breathing after apnea and to stabilize the O₂/CO₂ balance in blood. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the

A common type of industrial gas laser is the carbon dioxide laser. A laser is a device that emits Light ( Electromagnetic radiation) through a process called Stimulated emission. The carbon dioxide laser ( CO2 laser) was one of the earliest Gas lasers to be developed (invented by Kumar Patel of Bell Labs in 1964

Carbon dioxide can also be combined with limonene oxide from orange peels or other epoxides to create polymers and plastics. Limonene is a Hydrocarbon, classified as a cyclic Terpene. It is a colourless liquid at room temperatures with an extremely strong smell of oranges An epoxide is a cyclic Ether with only three ring atoms This ring approximately is an Equilateral triangle, i ^[10]

Carbon dioxide is used in enhanced oil recovery where it is injected into or adjacent to producing oil wells, usually under supercritical conditions. Enhanced Oil Recovery (abbreviated EOR is a generic term for techniques for increasing the amount of Oil that can be extracted from an Oil field. A supercritical fluid is any substance at a Temperature and Pressure above its Thermodynamic critical point. 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. Petroleum ( L petroleum, from Greek πετρέλαιον, lit ^[11] 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, carbonates and bicarbonates, and sodium salicylate. Urea is an Organic compound with the Chemical formula ( N[[hydrogen H]]22 C[[oxygen O]] In Chemistry, a carbonate is a salt or Ester of Carbonic acid. In Inorganic chemistry, bicarbonate ( IUPAC -recommended nomenclature hydrogencarbonate) is an intermediate form in the Deprotonation Sodium salicylate is a Sodium salt of Salicylic acid. It can be prepared from Sodium phenolate and Carbon dioxide under higher temperature

Liquid and solid carbon dioxide are important refrigerants, especially in the food industry, where they are employed during the transportation and storage of ice cream and other frozen foods. A refrigerant is a compound used in a heat cycle that undergoes a Phase change from a Gas to a Liquid and back 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 R-12 and is likely to enjoy a renaissance due to environmental concerns. Dichlorodifluoromethane ( R-12) usually sold under the Brand name Freon-12, is a Chlorofluorocarbon Halomethane, commonly known Its physical properties are highly favorable for cooling, refrigeration, and heating purposes, having a high volumetric cooling capacity. Due to its operation at pressures of up to 130 bars, CO₂ systems require highly resistant components that have been already developed to serial production in many sectors. In car air conditioning, in more than 90% of all driving conditions, R744 operates more efficiently than systems using R-134a. Its environmental advantages (GWP of 1, non-ozone depleting, non-toxic, non-flammable) could make it the future working fluid to replace current HFCs in cars, supermarkets, hot water heat pumps, among others. Global warming potential (GWP is a measure of how much a given mass of Greenhouse gas is estimated to contribute to Global warming. Some applications: Coca-Cola has fielded CO₂-based beverage coolers and the US Army is interested in CO₂ refrigeration and heating technology. The United States Army is a military organization whose primary mission is to "provide necessary forces and capabilities. ^[12][13]

By the end of 2007, the global car industry is expected to decide on the next-generation refrigerant in car air conditioning. CO₂ is one discussed option. (see The Cool War)

Enhanced Coal Bed Methane recovery (ECBM) is the process whereby carbon dioxide is pumped into the coal seam to displace methane thanks to higher CO2 adsorptivity. The Cool War refers to the debate about the next-generation refrigerant in car Air conditioning worldwide with an ongoing dispute between the Alliance for CO2 Enhanced coal bed methane recovery is a method of producing additional Coalbed methane from a Source rock, similar to Enhanced oil recovery applied to

In the Earth's atmosphere

Further information: Carbon dioxide in the Earth's atmosphere

Carbon dioxide in earth's atmosphere is considered a trace gas currently occurring at an average concentration of about 385 parts per million by volume or 582 parts per million by mass. Carbon dioxide forms approximately 004% of the Earth's atmosphere. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five The term Trace gas refers to a gas or gases which make up less than 1% by volume of the Earth's atmosphere, and therefore includes all gases except Nitrogen (78 The mass of the Earth atmosphere is 5. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five 14×10¹⁸ kg ^[14], so the total mass of atmospheric carbon dioxide is 3. 0×10¹⁵ kg (3,000 gigatonnes). Its concentration varies seasonally (see graph at right) and also considerably on a regional basis: in urban areas it is generally higher and indoors it can reach 10 times the background atmospheric concentration.

Carbon dioxide is a greenhouse gas. Greenhouse gases are gaseous constituents of the atmosphere bothnatural and anthropogenic that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared See greenhouse effect for more. The Greenhouse effect refers to the change in the Thermal equilibrium temperature of a planet or moon by the presence of an Atmosphere containing gas that absorbs

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 age of industrialization. Fossil fuels or mineral fuels are fossil source Fuels that is Hydrocarbons found within the top layer of the Earth’s crust. Deforestation is the conversion of Forested areas to non-forest land for use such as Arable land, Pasture, urban use logged area or wasteland The Industrial Revolution was a period in the late 18th and early 19th centuries when major changes in agriculture manufacturing and transportation had a profound effect on the ^[16] In 1999, 2,244,804,000 metric tons of CO₂ were produced in the U. S. as a result of electric energy generation. This is an output rate of 0. 6083 kg (1. 341 pounds) per kWh. ^[17]

Five hundred million years ago carbon dioxide was 20 times more prevalent than today, decreasing to 4-5 times during the Jurassic period and then maintained a slow decline until the industrial revolution, with a particularly swift reduction occurring 49 million years ago. The Jurassic is a geologic period and system that extends from about Ma (million years ago to  Ma that is from the end of the Triassic to the beginning The Industrial Revolution was a period in the late 18th and early 19th centuries when major changes in agriculture manufacturing and transportation had a profound effect on the The Azolla event occurred in the middle Eocene period around, when blooms of the freshwater Fern Azolla occurred in the Arctic Ocean ^[18][19]

Up to 40% of the gas emitted by some volcanoes during subaerial volcanic eruptions is carbon dioxide. Plate tectonics and hotspots Divergent plate boundaries At the Plate tectonics and hotspots Divergent plate boundaries At the ^[20] According to the best estimates, volcanoes release about 130-230 million tonnes (145-255 million tons) of CO₂ into the atmosphere each year. Carbon dioxide is also produced by hot springs such as those at the Bossoleto site near Rapolano Terme in Tuscany, Italy. Here, in a bowl-shaped depression of about 100 m diameter, local concentrations of CO₂ rise to above 75% overnight, sufficient to kill insects and small animals, but warm rapidly when sunlit and disperse by convection during the day^[21] Locally high concentrations of CO₂, produced by disturbance of deep lake water saturated with CO₂ are thought to have caused 37 fatalities at Lake Monoun, Cameroon in 1984 and 1700 casualties at Lake Nyos, Cameroon in 1986. Lake Monoun is a Lake in West Province, Cameroon that lies in the Oku Volcanic Field. The Republic of Cameroon is a unitary republic of central and western Africa. Lake Nyos is a Crater lake in the Northwest Province of Cameroon. ^[22] However, emissions of CO₂ by human activities are currently more than 130 times greater than the quantity emitted by volcanoes, amounting to about 27 billion tonnes per year (30 billion tons). ^[23]

In the oceans

There is about 50 times as much carbon dissolved in the oceans in the form of CO₂ and CO₂ hydration products as exists in the atmosphere. The oceans act as an enormous carbon sink, having "absorbed about one-third of all human-generated CO₂ emissions to date. "^[24] Generally, gas solubility decreases as water temperature increases. Accordingly carbon dioxide is released from ocean water into the atmosphere as ocean temperatures rise.

Most of the CO₂ taken up by the ocean forms carbonic acid. Some is consumed in photosynthesis by organisms in the water, and a small proportion of that sinks and leaves the carbon cycle. There is considerable concern that as a result of increased CO₂ in the atmosphere the acidity of seawater will increase and may adversely affect organisms living in the water. In particular, with increasing acidity, the availability of carbonates for forming shells decreases.

Biological role

Carbon dioxide is an end product in organisms that obtain energy from breaking down sugars, fats and amino acids with oxygen as part of their metabolism, in a process known as cellular respiration. In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. Cellular respiration is the set of the metabolic reactions and processes that take place in Organisms cells to convert biochemical energy from This includes all plants, animals, many fungi and some bacteria. In higher animals, the carbon dioxide travels in the blood from the body's tissues to the lungs where it is exhaled. In plants using photosynthesis, carbon dioxide is absorbed from the atmosphere.

Role in photosynthesis

Plants remove carbon dioxide from the atmosphere by photosynthesis, also called carbon assimilation, which uses light energy to produce organic plant materials by combining carbon dioxide and water. Carbon fixation is a process found in Autotrophs (organisms that produce their own food usually driven by Photosynthesis, whereby Carbon dioxide is changed Free oxygen is released as gas from the decomposition of water molecules, while the hydrogen is split into its protons and electrons and used to generate chemical energy via photophosphorylation. The production of ATP using the energy of sunlight is called photophosphorylation. This energy is required for the fixation of carbon dioxide in the Calvin cycle to form sugars. The Calvin cycle (or Calvin-Benson-Bassham cycle or carbon fixation is a series of biochemical reactions that takes place in the Stroma of Chloroplasts These sugars can then be used for growth within the plant through respiration.

Even when vented, carbon dioxide must be introduced into greenhouses to maintain plant growth, as the concentration of carbon dioxide can fall during daylight hours to as low as 200 ppm (a limit of C3 carbon fixation photosynthesis). carbon fixation is a Metabolic pathway for Carbon fixation in Photosynthesis. Plants can potentially grow up to 50 percent faster in concentrations of 1,000 ppm CO₂ when compared with ambient conditions. ^[25]

Plants also emit CO₂ during respiration, so it is only during growth stages that plants are net absorbers. For example a growing forest will absorb many tons of CO₂ each year, however a mature forest will produce as much CO₂ from respiration and decomposition of dead specimens (e. g. fallen branches) as used in biosynthesis in growing plants. Biosynthesis is a phenomenon wherein Chemical compounds are produced from simpler Reagents Biosynthesis unlike Chemosynthesis, takes place within living ^[26] Regardless of this, mature forests are still valuable carbon sinks, helping maintain balance in the Earth's atmosphere. Additionally, and crucially to life on earth, phytoplankton photosynthesis absorbs dissolved CO₂ in the upper ocean and thereby promotes the absorption of CO₂ from the atmosphere. ^[27]

Toxicity

Carbon dioxide content in fresh air varies between 0. 03% (300 ppm) and 0. 06% (600 ppm), depending on the location (see graphical map of CO₂ in real-time).

According to the Australian Maritime Safety Authority, "Prolonged exposure to moderate concentrations can cause acidosis and adverse effects on calcium phosphorus metabolism resulting in increased calcium deposits in soft tissue. Carbon dioxide is toxic to the heart and causes diminished contractile force. At concentrations of three per cent by volume in air, it is mildly narcotic and causes increased blood pressure and pulse rate, and causes reduced hearing. At concentrations of about five per cent by volume it causes stimulation of the respiratory centre, dizziness, confusion and difficulty in breathing accompanied by headache and shortness of breath. At about eight per cent concentration it causes headache, sweating, dim vision, tremor and loss of consciousness after exposure for between five and ten minutes. " ^[28]

Due to the health risks associated with carbon dioxide exposure, the U. S. Occupational Safety and Health Administration says that average exposure for health adults during an eight-hour work day should not exceed 5,000 ppm (0. 5%). The maximum safe level for infants, children, the elderly and individuals with cardio-pulmonary health issues is significantly less. For short-term (under ten minutes) exposure, the U. S. National Institute for Occupational Safety and Health (NIOSH) and American Conference of Government Industrial Hygienists (ACGIH) limit is 30,000 ppm (3%). NIOSH also states that carbon dioxide concentrations exceeding 4% are immediately dangerous to life and health. ^[29]

Adaptation to increased levels of CO₂ occurs in humans. Continuous inhalation of CO₂ can be tolerated at three percent inspired concentrations for at least one month and four percent inspired concentrations for over a week. It was suggested that 2. 0 percent inspired concentrations could be used for closed air spaces (ex. Submarine) since the adaptation is physiological and reversible. A submarine is a Watercraft that can operate independently below water as distinct from a Submersible that has only limited underwater capability Decrement in performance or in normal physical activity does not happen at this level. ^[30][31]

These figures are valid for pure carbon dioxide. In indoor spaces occupied by people the carbon dioxide concentration will reach higher levels than in pure outdoor air. Concentrations higher than 1,000 ppm will cause discomfort in more than 20% of occupants, and the discomfort will increase with increasing CO₂ concentration. The discomfort will be caused by various gases coming from human respiration and perspiration, and not by CO₂ itself. At 2,000 ppm the majority of occupants will feel a significant degree of discomfort, and many will develop nausea and headaches. The CO₂ concentration between 300 and 2,500 ppm is used as an indicator of indoor air quality.

Acute carbon dioxide toxicity is sometimes known as by the names given to it by miners: blackdamp (also called choke damp or stythe). Blackdamp (also known as stythe or choke damp) is a mixture of unbreathable gases formed when oxygen is removed from an enclosed Atmosphere and largely Miners would try to alert themselves to dangerous levels of carbon dioxide in a mine shaft by bringing a caged canary with them as they worked. Mining is the extraction of valuable Minerals or other geological materials from the earth usually (but not always from an Ore body The canary would inevitably die before CO₂ reached levels toxic to people. Carbon dioxide caused a great loss of life at Lake Nyos in Cameroon in 1986, when an upwelling of CO₂-laden lake water quickly blanketed a large surrounding populated area. Lake Nyos is a Crater lake in the Northwest Province of Cameroon. The Republic of Cameroon is a unitary republic of central and western Africa. ^[32] The heavier carbon dioxide forced out the life-sustaining oxygen near the surface, killing nearly two thousand people.

Carbon dioxide ppm levels (CDPL) are a surrogate for measuring indoor pollutants that may cause occupants to grow drowsy, get headaches, or function at lower activity levels. To eliminate most Indoor Air Quality complaints, total indoor CDPL must be reduced to below 600. Indoor Air Quality (IAQ deals with the content of interior air that could affect health and comfort of building occupants NIOSH considers that indoor air concentrations that exceed 1,000 are a marker suggesting inadequate ventilation. The National Institute for Occupational Safety and Health (or NIOSH) is the United States federal agency responsible for conducting research and making recommendations ASHRAE recommends they not exceed 1,000 inside a space. The American Society of Heating Refrigerating and Air Conditioning Engineers ( ASHRAE; pronounced 'ash'-'ray' is an international technical society for all individuals

Human physiology

See also: Arterial blood gas

CO₂ is carried in blood in three different ways. An arterial blood gas ( ABG) is a Blood test that is performed specifically on Blood from an Artery. (The exact percentages vary depending whether it is arterial or venous blood).

• Most of it (about 70% – 80%) is converted to bicarbonate ions HCO₃⁻ by the enzyme carbonic anhydrase in the red blood cells,^[33] by the reaction CO₂ + H₂O → H₂CO₃ → H⁺ + HCO₃⁻. In Inorganic chemistry, bicarbonate ( IUPAC -recommended nomenclature hydrogencarbonate) is an intermediate form in the Deprotonation The carbonic anhydrases (or carbonate dehydratases) form a family of Enzymes that catalyze the rapid conversion of Carbon dioxide to Bicarbonate

• 5% – 10% is dissolved in the plasma^[33]

• 5% – 10% is bound to hemoglobin as carbamino compounds^[33]

The CO₂ bound to hemoglobin does not bind to the same site as oxygen. Blood plasma is the Liquid component of Blood, in which the Blood cells are suspended Hemoglobin ( also spelled haemoglobin and abbreviated Hb or Hgb) is the Iron -containing Oxygen -transport Metalloprotein Carbamino refers to a compound composed by the addition of Carbon dioxide with a free Amino group in an Amino acid or a Protein, such as Instead, it combines with the N-terminal groups on the four globin chains. However, because of allosteric effects on the hemoglobin molecule, the binding of CO₂ decreases the amount of oxygen that is bound for a given partial pressure of oxygen. In Biochemistry, allosteric regulation is the regulation of an Enzyme or other Protein by binding an effector molecule at the protein's allosteric

Hemoglobin, the main oxygen-carrying molecule in red blood cells, can carry both oxygen and carbon dioxide, although in quite different ways. Hemoglobin ( also spelled haemoglobin and abbreviated Hb or Hgb) is the Iron -containing Oxygen -transport Metalloprotein Red blood cells are the most common type of Blood cell and the Vertebrate body's principal means of delivering Oxygen to the body tissues via the Blood The decreased binding to carbon dioxide in the blood due to increased oxygen levels is known as the Haldane Effect, and is important in the transport of carbon dioxide from the tissues to the lungs. The Haldane effect is a property of Hemoglobin first described by the Scottish Physician John Scott Haldane. Conversely, a rise in the partial pressure of CO₂ or a lower pH will cause offloading of oxygen from hemoglobin. This is known as the Bohr Effect. Bohr effect is a property of Hemoglobin first described in 1904 by the Danish physiologist Christian Bohr (father of physicist Niels Bohr) which states

Carbon dioxide may be one of the mediators of local autoregulation of blood supply. Autoregulation is a specific form of Homeostasis used to describe the tendency of the body to keep Blood flow constant when blood pressure varies If its levels are high, the capillaries expand to allow a greater blood flow to that tissue. Capillaries are the smallest of a body's Blood vessels measuring 5-10 μm in diameter which connect Arterioles and Venules and enable the interchange

Bicarbonate ions are crucial for regulating blood pH. A person's breathing rate influences the level of CO₂ in their blood. Breathing that is too slow or shallow can cause respiratory acidosis, while breathing that is too rapid may lead to hyperventilation, which may cause respiratory alkalosis. Respiratory acidosis is Acidosis (abnormally increased acidity of the blood due to decreased ventilation of the pulmonary Alveoli, leading to In Medicine, hyperventilation (or overbreathing) is the state of Breathing faster and/or deeper than necessary bringing about lightheadedness and other Alkalosis refers to a condition reducing Hydrogen ion concentration of arterial Blood plasma ( alkalemia)

Although the body requires oxygen for metabolism, low oxygen levels do not stimulate breathing. Rather, breathing is stimulated by higher carbon dioxide levels. As a result, breathing low-pressure air or a gas mixture with no oxygen at all (such as pure nitrogen) may lead to loss of consciousness. This is especially perilous for high-altitude fighter pilots. It is also why flight attendants instruct passengers, in case of loss of cabin pressure, to apply the oxygen mask to themselves first before helping others — otherwise one risks going unconscious without being aware of the imminent peril. ^[33]

According to a study by the United States Department of Agriculture, an average person's respiration generates approximately 450 liters (roughly 900 grams) of carbon dioxide per day. ^[34]

See also

References

External links

• International Chemical Safety Card 0021
• CID 280 from PubChem
• CO₂ Carbon Dioxide Properties, Uses, Applications
• Pressure-Temperature phase diagram for carbon dioxide
• Molview from bluerhinos.co.uk See Carbon dioxide in 3D
• Dry Ice information
• Trends in Atmospheric Carbon Dioxide (NOAA)
• Phase Diagram of Carbon Dioxide
• Experiment 071 -- Triple Point Phase Transition for Carbon Dioxide
• CO₂ as a natural refrigerant - FAQs
• Methods to reduce carbon dioxide emmisions from power plants

PubChem is a Database of chemical Molecules The system is maintained by the National Center for Biotechnology Information (NCBI a component

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