Phys.org - carbon ( ... sorted: popular/1d)

Home
carbon
sorted by popularity

Related topics:

carbon dioxide · climate change · carbon nanotube · greenhouse gas emissions · atmosphere

New method for producing clean hydrogen

Duke University engineers have developed a novel method for producing clean hydrogen, which could prove essential to weaning society off of fossil fuels and their environmental implications.

Chemistry - Materials Science

May 21, 2013

4.6 / 5 (20)

9 |

Long-term warming, short-term variability: Why climate change is still an issue

A new study published yesterday suggests that the short-term warming due to increasing greenhouse gases may be less than previously feared. However, when we look at the bigger picture, we still find that cli ...

Space & Earth - Earth Sciences

May 21, 2013

5 / 5 (7)

1

Unexpected effects of ocean acidification on deep-sea organisms

About 55.5 million years ago, geologically rapid emission of a large volume of greenhouse gases at the Paleocene-Eocene boundary (PETM) led to global warming of about 5oC, severe ocean acidification, and ...

Space & Earth - Environment

12 hours ago

3.7 / 5 (3)

0 |

Coccoliths thrive despite ocean acidification

Ocean acidification is damaging some marine species while others thrive, say scientists. An international team studied the effect of ocean acidification on plankton in the North Sea over the past forty years, ...

Biology - Ecology

12 hours ago

5 / 5 (2)

1 |

Bacterial spare parts filter antibiotic residue from groundwater

Researchers at University of Cincinnati have developed and tested a solar-powered nano filter that is able to remove harmful carcinogens and antibiotics from water sources – lakes and rivers – at a significantly higher ...

Biology - Cell & Microbiology

May 21, 2013

4.5 / 5 (2)

2

Study finds the bulk of shoes' carbon footprint comes from manufacturing processes

A typical pair of running shoes generates 30 pounds of carbon dioxide emissions, equivalent to keeping a 100-watt light bulb on for one week, according to a new MIT-led lifecycle assessment. But what's surprising ...

Technology - Energy & Green Tech

12 hours ago

3 / 5 (2)

5 |

Carbon

Carbon (pronounced /ˈkɑrbən/) is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5730 years. Carbon is one of the few elements known since antiquity. The name "carbon" comes from Latin language carbo, coal, and, in some Romance and Slavic languages, the word carbon can refer both to the element and to coal.

There are several allotropes of carbon of which the best known are graphite, diamond, and amorphous carbon. The physical properties of carbon vary widely with the allotropic form. For example, diamond is highly transparent, while graphite is opaque and black. Diamond is among the hardest materials known, while graphite is soft enough to form a streak on paper (hence its name, from the Greek word "to write"). Diamond has a very low electrical conductivity, while graphite is a very good conductor. Under normal conditions, diamond has the highest thermal conductivity of all known materials. All the allotropic forms are solids under normal conditions but graphite is the most thermodynamically stable.

All forms of carbon are highly stable, requiring high temperature to react even with oxygen. The most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and other transition metal carbonyl complexes. The largest sources of inorganic carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil and methane clathrates. Carbon forms more compounds than any other element, with almost ten million pure organic compounds described to date, which in turn are a tiny fraction of such compounds that are theoretically possible under standard conditions.

Carbon is one of the least abundant elements in the Earth's crust, but the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known lifeforms, and in the human body carbon is the second most abundant element by mass (about 18.5%) after oxygen. This abundance, together with the unique diversity of organic compounds and their unusual polymer-forming ability at the temperatures commonly encountered on Earth, make this element the chemical basis of all known life.

This text uses material from Wikipedia, licensed under CC BY-SA

Subscribe to rss feed