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[[Image:CO2.gif|thumb|left|150px|The bonds of Carbon Dioxide]]

[[Image:CO2.gif|thumb|left|150px|The bonds of Carbon Dioxide]]

'''Carbon dioxide''' (CO₂) is an odorless, colorless [[gas]] formed by the [[oxidation]] of [[hydrocarbon]]s, both naturally, in animals, and artificially, as fuel<ref>If not enough oxygen is present, [[carbon monoxide]] will also be produced, in a process called [[incomplete combustion]].</ref>. It is the second simplest oxycarbon, after [[Carbon Monoxide]]. The structure of Carbon Dioxide is that of a single carbon atom, double bonded to two oxygen atoms. It is one of the [[human]] body's major waste products, being excreted through exhalation (breathing).

'''Carbon dioxide''' (CO₂) is an odorless, colorless [[gas]] formed by the [[oxidation]] of [[hydrocarbon]]s, both naturally, in animals, and artificially, as fuel.<ref>If not enough oxygen is present, [[carbon monoxide]] will also be produced, in a process called [[incomplete combustion]].</ref>  

It is used by [[plants]] in the process of [[photosynthesis]] to create complex carbohydrates ([[cellulose]] and [[sugar]]s), using water and the [[energy]] from sunlight. The waste product in this process is [[oxygen]].  ''Carbon dioxide is not a pollutant, but a pervasive byproduct of life''. CO₂ should be called an "emission", not a "pollutant", in debates about [[global warming]].

It is used by [[plants]] in the process of [[photosynthesis]] to create complex carbohydrates ([[cellulose]] and [[sugar]]s), using water and the [[energy]] from [[sunlight]].  The waste product in this process is [[oxygen]].

It is one of the [[human]] body's major waste products, being excreted through exhalation (breathing).   

At room temperature and atmospheric [[pressure]], carbon dioxide is a gas. It becomes solid at -78 ºC at standard atmospheric pressure, forming [[dry ice]]. When it thaws, it turns directly into a gas again (called [[sublimation]]). <ref>"Dry ice is frozen carbon dioxide. A block of dry ice has a surface temperature of -109.3 degrees Fahrenheit (-78.5 degrees C). Dry ice also has the very nice feature of sublimation -- as it breaks down, it turns directly into carbon dioxide gas rather than a liquid." [http://www.howstuffworks.com/question264.htm How Stuff Works] </ref> This can be seen from the phase diagram to the right, where at 1 atmosphere of pressure, there is no liquid state separating the solid and gas as temperature rises.

It is the second simplest [[oxycarbon]], after [[Carbon Monoxide]]. The structure of Carbon Dioxide is that of a single carbon atom, double bonded to two oxygen atoms.  

CO₂ is one of the [[greenhouse gas]]es.  Heat-trapping by CO₂ has been observed on [[Earth]] and [[Venus]].  The extent of its role in the current increase in average global temperatures is a topic of active political and scientific debate. Rising CO₂ levels in the atmosphere have been observed to promote acidification of the oceans, through CO₂ + H₂O => H2CO3

The [[Lewis structure]] indicates it has two double bonds,

The [[Lewis structure]] indicates it has two double bonds,

At room temperature and atmospheric [[pressure]], carbon dioxide is a gas. It becomes solid at -78&nbsp;°C at standard atmospheric pressure, forming [[dry ice]]. When it thaws, it turns directly into a gas again (called [[sublimation]]).<ref>"Dry ice is frozen carbon dioxide. A block of dry ice has a surface temperature of -109.3 degrees Fahrenheit (-78.5 degrees C). Dry ice also has the very nice feature of sublimation -- as it breaks down, it turns directly into carbon dioxide gas rather than a liquid." [http://www.howstuffworks.com/question264.htm How Stuff Works]</ref> This can be seen from the phase diagram to the right, where at 1 atmosphere of pressure, there is no liquid state separating the solid and gas as temperature rises.

 

There is no catalytic converter for CO₂, in contrast with the emissions control device used for automobiles.

==Carbon Dioxide and Atmospheric Temperature==

==Carbon Dioxide and Atmospheric Temperature==

The effects of an increased level of CO₂ is Increased [[plant]] growth, as CO₂(g) + 12H₂O(aq) + energy → C₆H₁₂O₆(aq)(A complex sugar) + 6O₂(gas) + 6H₂O(aq), as more products for photosynthesis. This supposedly has beneficial effects for humans, such as greater crop yields and alleviating the effects of a growing human population.

CO₂ is one of the "[[greenhouse gas]]es".  Heat-trapping by CO₂ has been observed on [[Earth]] and [[Venus]].  The extent of its role in the current increase in average global temperatures is a topic of active political and scientific debate. Rising CO₂ levels in the atmosphere have been observed to promote acidification of the oceans, through CO₂ + H₂O → H₂CO₃.

 

[[Environmentalist]]s predict catastrophic [[global warming]] scenarios at the hands of excessive CO₂ released by industrial and commercial activities. A counterargument to this theory is that, the planet naturally gives off carbon dioxide, from natural sources such as volcanoes, and thus, it is not so bad for the Earth.

 

The effects of an increased level of CO₂ is increased [[plant]] growth since carbon dioxide is a reactant of the photosynthesis reaction, meaning that more CO₂ gives plants more energy, hence increased growth. This supposedly has beneficial effects for humans, such as greater crop yields and alleviating the effects of a growing human population.

==See also==

==See also==

*[[Carbon dioxide in the atmosphere]]

*[[Carbon dioxide in the atmosphere]]

==References==

==References==

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[[Category: Chemical Compounds]]

[[Category:Chemical Compounds]]