Related topics: climate change , greenhouse gas , global warming , fossil fuels , carbon dioxide emissions
Carbon dioxide
hideCarbon 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.
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. Large 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. 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 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.
CO2 is toxic in higher concentrations: 1% (10,000 ppm) will make some people feel drowsy. Concentrations of 7% to 10% cause dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.
For more information about Carbon dioxide, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with carbon dioxide
Researchers engineer bacteria to turn carbon dioxide into liquid fuel
Dec 10, 2009 |
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(PhysOrg.com) -- The genetically modified cyanobacterium consumes carbon dioxide and produces the liquid fuel isobutanol by using energy from sunlight.
Machine Converts CO2 into Gasoline, Diesel, and Jet Fuel
Nov 23, 2009 |
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(PhysOrg.com) -- Researchers at Sandia National Laboratories have built a machine that uses the sun's energy to convert carbon dioxide waste from power plants into transportation fuels such as gasoline, diesel, ...
Controversial new climate change results
Nov 10, 2009 |
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(PhysOrg.com) -- New data show that the balance between the airborne and the absorbed fraction of CO2 has stayed approximately constant since 1850, despite emissions of CO2 having risen from about 2 billion ...
Researchers identify dominant chemical that attracts mosquitoes to humans
Oct 26, 2009 |
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Scientists at the University of California, Davis, have identified the dominant odor naturally produced in humans and birds that attracts the blood-feeding Culex mosquitoes, which transmit West Nile virus ...
Ultracapacitors Make City Buses Cheaper, Greener
Oct 21, 2009 |
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(PhysOrg.com) -- A fleet of 17 buses near Shanghai has been running on ultracapacitors for the past three years, and today that technology is coming to the Washington, DC, for a one-day demonstration. Chinese ...
Scientists discover protein receptor for carbonation taste
Oct 15, 2009 |
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(PhysOrg.com) -- In 1767, chemist Joseph Priestley stood in his laboratory one day with an idea to help English mariners stay healthy on long ocean voyages. He infused water with carbon dioxide to create an effervescent ...
Last time carbon dioxide levels were this high: 15 million years ago, scientists report
Space & Earth / Earth Sciences
Oct 08, 2009 |
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You would have to go back at least 15 million years to find carbon dioxide levels on Earth as high as they are today, a UCLA scientist and colleagues report Oct. 8 in the online edition of the journal Science.
Cockroaches Control Their Breathing to Save Water
Sep 24, 2009 |
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(PhysOrg.com) -- Many insects have been known for decades to hold their breath when resting, but the reasons have not been well understood. A new study on cockroaches suggests the insects reduce their breathing ...
Scientists propose new hypothesis on the origin of life
Space & Earth / Earth Sciences
Sep 04, 2009 |
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The Miller-Urey experiment, conducted by chemists Stanley Miller and Harold Urey in 1953, is the classic experiment on the origin of life. It established that the early Earth atmosphere, as they pictured it, ...
Forests of Artificial Trees Could Slow Global Warming
Aug 28, 2009 |
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(PhysOrg.com) -- A new study on how technology could help to regulate climate change has studied hundreds of ideas, and selected three considered practical and able to be implemented quickly. The report's ...
Opening the Door for CO2
Aug 24, 2009 |
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(PhysOrg.com) -- Until recently, factory smokestacks that produced nothing but carbon dioxide and water vapor were considered exemplary. Now CO2 has become notorious as a greenhouse gas, and the danger of climate change has ...
Scientists Make Oxygen Out of Moon Rock
Space & Earth / Space Exploration
Aug 11, 2009 |
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(PhysOrg.com) -- If humans ever create a lunar base, one of the biggest challenges will be figuring out how to breathe. Transporting oxygen to the moon is extremely expensive, so for the past several years ...
Long debate ended over cause, demise of ice ages -- may also help predict future
Space & Earth / Earth Sciences
Aug 06, 2009 |
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Researchers have largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years - they are ultimately linked to slight shifts in solar radiation caused ...
More than meets the eye: New blue light nanocrystals
Nanotechnology / Nanomaterials
Jul 21, 2009 |
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Berkeley Lab researchers have produced non-toxic magnesium oxide nanocrystals that efficiently emit blue light and could also play a role in long-term storage of carbon dioxide, a potential means of tempering ...
Global warming: Our best guess is likely wrong
Space & Earth / Earth Sciences
Jul 14, 2009 |
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No one knows exactly how much Earth's climate will warm due to carbon emissions, but a new study this week suggests scientists' best predictions about global warming might be incorrect.
