Carbonic acid

Carbonic acid is a chemical compound with the chemical formula H₂CO₃ (equivalently OC(OH)₂). It is also a name sometimes given to solutions of carbon dioxide in water (carbonated water), because such solutions contain small amounts of H₂CO₃. In physiology, carbonic acid is described as volatile acid or respiratory acid, because it is the only acid excreted as a gas by the lungs.

Carbonic acid, which is a weak acid, forms two kinds of salts, the carbonates and the bicarbonates. In geology, carbonic acid causes limestone to dissolve producing calcium bicarbonate which leads to many limestone features such as stalactites and stalagmites.

The long-held belief that carbonic acid could not exist as a pure compound has reportedly been recently disproved by the preparation of the pure substance in both solid and gas form by University of Innsbruck researchers.

Chemical equilibrium

When carbon dioxide dissolves in water it exists in chemical equilibrium producing carbonic acid:

The hydration equilibrium constant at 25 °C is called K_h, which in the case of carbonic acid is [H₂CO₃]/[CO₂] ≈ 1.7×10⁻³ in pure water and ≈ 1.2×10⁻³ in seawater. Hence, the majority of the carbon dioxide is not converted into carbonic acid, remaining as CO₂ molecules. In the absence of a catalyst, the equilibrium is reached quite slowly. The rate constants are 0.039 s⁻¹ for the forward reaction (CO₂ + H₂O → H₂CO₃) and 23 s⁻¹ for the reverse reaction (H₂CO₃ → CO₂ + H₂O). Carbonic acid is used in the making of soft drinks, inexpensive and artificially carbonated sparkling wines, and other bubbly drinks. The addition of two molecules of water to CO₂ would give orthocarbonic acid, C(OH)₄, which exists only in minute amounts in aqueous solution.

Volatility (finance)

In finance, volatility is the degree of variation of a trading price series over time as measured by the standard deviation of returns.

Historic volatility is derived from time series of past market prices. An implied volatility is derived from the market price of a market traded derivative (in particular an option). The symbol σ is used for volatility, and corresponds to standard deviation, which should not be confused with the similarly named variance, which is instead the square, σ².

Volatility terminology

Volatility as described here refers to the actual current volatility of a financial instrument for a specified period (for example 30 days or 90 days). It is the volatility of a financial instrument based on historical prices over the specified period with the last observation the most recent price. This phrase is used particularly when it is wished to distinguish between the actual current volatility of an instrument.

Volatile (A Hero A Fake album)

Volatile is the debut album by American metalcore band A Hero A Fake, released on October 28, 2008 through Victory Records. A music video for the album's single, I Know I, was produced by Scott Hansen and premiered on MTV2 on February 21, 2009.

Track listing

All lyrics written by Justin Brown, all music composed by A Hero A Fake.

Personnel

† filed for name change to Alex Avigliano

References

Nature

Nature, in the broadest sense, is the natural, physical, or material world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large part of science. Although humans are part of nature, human activity is often understood as a separate category from other natural phenomena.

The word nature is derived from the Latin word natura, or "essential qualities, innate disposition", and in ancient times, literally meant "birth".Natura is a Latin translation of the Greek word physis (φύσις), which originally related to the intrinsic characteristics that plants, animals, and other features of the world develop of their own accord. The concept of nature as a whole, the physical universe, is one of several expansions of the original notion; it began with certain core applications of the word φύσις by pre-Socratic philosophers, and has steadily gained currency ever since. This usage continued during the advent of modern scientific method in the last several centuries.

Nature (journal)

Nature is a British interdisciplinary scientific journal, first published on 4 November 1869. It was ranked the world's most cited scientific journal by the Science Edition of the 2010 Journal Citation Reports, is ascribed an impact factor of approximately 42.4, and is widely regarded as one of the few remaining academic journals that publishes original research across a wide range of scientific fields.Nature claims an online readership of about 3 million unique readers per month. The journal has a weekly circulation of around 53,000 but studies have concluded that on average a single copy is shared by as many as eight people.

Research scientists are the primary audience for the journal, but summaries and accompanying articles are intended to make many of the most important papers understandable to scientists in other fields and the educated public. Towards the front of each issue are editorials, news and feature articles on issues of general interest to scientists, including current affairs, science funding, business, scientific ethics and research breakthroughs. There are also sections on books and arts. The remainder of the journal consists mostly of research papers (articles or letters), which are often dense and highly technical. Because of strict limits on the length of papers, often the printed text is actually a summary of the work in question with many details relegated to accompanying supplementary material on the journal's website.

Mother Nature

Mother Nature (sometimes known as Mother Earth or the Earth-Mother), is a common personification of nature that focuses on the life-giving and nurturing aspects of nature by embodying it ,in the form of the mother.

Western tradition history

The word "nature" comes from the Latin word, "natura," meaning birth or character (see nature (innate)). In English its first recorded use (in the sense of the entirety of the phenomena of the world) was in 1266 A.D.. "Natura", and the personification of Mother Nature, was widely popular in the Middle Ages. As a concept, seated between the properly divine and the human, it can be traced to Ancient Greece, though Earth (or "Eorthe" in the Old English period) may have been personified as a goddess. The Norse also had a goddess called Jord (or Earth).

The earliest written dated literal references to the term "Mother Earth" occur in Mycenaean Greek. Ma-ka (transliterated as ma-ga), "Mother Gaia", written in Linear B syllabic script (13th or 12th century BC). The various myths of nature goddesses such as Inanna/Ishtar (myths and hymns attested on Mesopotamian tablets as early as the 3rd millennium BC) show that the personification of the creative and nurturing sides of nature as female deities has deep roots. In Greece, the pre-Socratic philosophers had "invented" nature when they abstracted the entirety of phenomena of the world as singular: physis, and this was inherited by Aristotle. Later medieval Christian thinkers did not see nature as inclusive of everything, but thought that she had been created by God; her place lay on earth, below the unchanging heavens and moon. Nature lay somewhere in the center, with agents above her (angels), and below her (demons and hell). For the medieval mind she was only a personification, not a goddess.