01-31-2010, 06:24 AM
Carbon dioxide
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"CO2" redirects here. For the UK postal district, see CO postcode area.
Carbon dioxide
IUPAC name[hide]Carbon dioxide
other names[hide]Carbonic acid gas; carbonic anhydride; dry ice (solid)
Identifiers
CAS number 124-38-9 Y
PubChem 280
ChemSpider 274
EC number 204-696-9
UN number 1013
Solid (dry ice): 1845
Mixtures with Ethylene oxide: 1952,3300
RTECS number FF6400000
SMILES [show]
O=C=O
InChI [show]
1/CO2/c2-1-3
InChI key CURLTUGMZLYLDI-UHFFFAOYAO
Properties
Molecular formula CO2
Molar mass 44.010 g/mol
Appearance colorless, odorless gas
Density 1.562 g/mL (solid at 1 atm and −78.5 °C)
0.770 g/mL (liquid at 56 atm and 20 °C)
1.977 g/L (gas at 1 atm and 0 °C)
849.6 g/L (supercritical fluid at 150 atm and 30 °C
Melting point -78 °C, 194.7 K, -109 °F (subl.)
Boiling point -57 °C, 216.6 K, -70 °F (at 5.185 bar)
Solubility in water 1.45 g/L at 25 °C, 100 kPa
Acidity (pKa) 6.35, 10.33
Refractive index (nD) 1.1120
Viscosity 0.07 cP at −78 °C
Dipole moment zero
Structure
Molecular shape linear
Related compounds
Other anions Carbon disulfide
Other cations Silicon dioxide
Germanium dioxide
Tin dioxide
Lead dioxide
Related carbon oxides Carbon monoxide
Carbon suboxide
Dicarbon monoxide
Carbon trioxide
Related compounds Carbonic acid
Carbonyl sulfide
Supplementary data page
Structure and
properties n, εr, etc.
Thermodynamic
data Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Y (what is this?) (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
Carbon dioxide (chemical formula CO2) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state. CO2 is a trace gas being only 0.038% of the atmosphere.
Carbon dioxide is used by plants during photosynthesis to make sugars, which may either be consumed in respiration or used as the raw material to produce other organic compounds needed for plant growth and development. It is produced during respiration by plants, and by all animals, fungi and microorganisms that depend either directly or indirectly on plants for food. It is thus a major component of the carbon cycle. Carbon dioxide is generated as a by-product of the combustion of fossil fuels or the burning of vegetable matter, among other chemical processes. Small amounts of carbon dioxide are emitted from volcanoes and other geothermal processes such as hot springs and geysers and by the dissolution of carbonates in crustal rocks.
As of March 2009[update], carbon dioxide in the Earth's atmosphere is at a concentration of 387 ppm by volume.[1] Atmospheric concentrations of carbon dioxide fluctuate slightly with the change of the seasons, driven primarily by seasonal plant growth in the Northern Hemisphere. Concentrations of carbon dioxide fall during the northern spring and summer as plants consume the gas, and rise during the northern autumn and winter as plants go dormant, die and decay. Carbon dioxide is a greenhouse gas as it transmits visible light but absorbs strongly in the infrared and near-infrared.
Carbon dioxide has no liquid state at pressures below 5.1 atmospheres. At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78 °C (−108.4 °F; 195.1 K) and the solid sublimes directly to a gas above −78 °C. In its solid state, carbon dioxide is commonly called dry ice.
CO2 is an acidic oxide: an aqueous solution turns litmus from blue to pink. It is the anhydride of carbonic acid, an acid which is unstable and is known to exist only in aqueous solution. In organisms carbonic acid production is catalysed by the enzyme, carbonic anhydrase.
CO2 + H2O ⇌ H2CO3
CO2 is toxic in higher concentrations: 1% (10,000 ppm) will make some people feel drowsy.[2] Concentrations of 7% to 10% cause dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.[3]
From Wikipedia, the free encyclopedia
Jump to: navigation, search
"CO2" redirects here. For the UK postal district, see CO postcode area.
Carbon dioxide
IUPAC name[hide]Carbon dioxide
other names[hide]Carbonic acid gas; carbonic anhydride; dry ice (solid)
Identifiers
CAS number 124-38-9 Y
PubChem 280
ChemSpider 274
EC number 204-696-9
UN number 1013
Solid (dry ice): 1845
Mixtures with Ethylene oxide: 1952,3300
RTECS number FF6400000
SMILES [show]
O=C=O
InChI [show]
1/CO2/c2-1-3
InChI key CURLTUGMZLYLDI-UHFFFAOYAO
Properties
Molecular formula CO2
Molar mass 44.010 g/mol
Appearance colorless, odorless gas
Density 1.562 g/mL (solid at 1 atm and −78.5 °C)
0.770 g/mL (liquid at 56 atm and 20 °C)
1.977 g/L (gas at 1 atm and 0 °C)
849.6 g/L (supercritical fluid at 150 atm and 30 °C
Melting point -78 °C, 194.7 K, -109 °F (subl.)
Boiling point -57 °C, 216.6 K, -70 °F (at 5.185 bar)
Solubility in water 1.45 g/L at 25 °C, 100 kPa
Acidity (pKa) 6.35, 10.33
Refractive index (nD) 1.1120
Viscosity 0.07 cP at −78 °C
Dipole moment zero
Structure
Molecular shape linear
Related compounds
Other anions Carbon disulfide
Other cations Silicon dioxide
Germanium dioxide
Tin dioxide
Lead dioxide
Related carbon oxides Carbon monoxide
Carbon suboxide
Dicarbon monoxide
Carbon trioxide
Related compounds Carbonic acid
Carbonyl sulfide
Supplementary data page
Structure and
properties n, εr, etc.
Thermodynamic
data Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Y (what is this?) (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
Carbon dioxide (chemical formula CO2) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state. CO2 is a trace gas being only 0.038% of the atmosphere.
Carbon dioxide is used by plants during photosynthesis to make sugars, which may either be consumed in respiration or used as the raw material to produce other organic compounds needed for plant growth and development. It is produced during respiration by plants, and by all animals, fungi and microorganisms that depend either directly or indirectly on plants for food. It is thus a major component of the carbon cycle. Carbon dioxide is generated as a by-product of the combustion of fossil fuels or the burning of vegetable matter, among other chemical processes. Small amounts of carbon dioxide are emitted from volcanoes and other geothermal processes such as hot springs and geysers and by the dissolution of carbonates in crustal rocks.
As of March 2009[update], carbon dioxide in the Earth's atmosphere is at a concentration of 387 ppm by volume.[1] Atmospheric concentrations of carbon dioxide fluctuate slightly with the change of the seasons, driven primarily by seasonal plant growth in the Northern Hemisphere. Concentrations of carbon dioxide fall during the northern spring and summer as plants consume the gas, and rise during the northern autumn and winter as plants go dormant, die and decay. Carbon dioxide is a greenhouse gas as it transmits visible light but absorbs strongly in the infrared and near-infrared.
Carbon dioxide has no liquid state at pressures below 5.1 atmospheres. At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78 °C (−108.4 °F; 195.1 K) and the solid sublimes directly to a gas above −78 °C. In its solid state, carbon dioxide is commonly called dry ice.
CO2 is an acidic oxide: an aqueous solution turns litmus from blue to pink. It is the anhydride of carbonic acid, an acid which is unstable and is known to exist only in aqueous solution. In organisms carbonic acid production is catalysed by the enzyme, carbonic anhydrase.
CO2 + H2O ⇌ H2CO3
CO2 is toxic in higher concentrations: 1% (10,000 ppm) will make some people feel drowsy.[2] Concentrations of 7% to 10% cause dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.[3]