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Meteorite hunt goes on, needs public's help

(Phys.org) -- A University of California, Davis, geologist is appealing for public help in tracking down pieces of the meteorite that blew up over El Dorado County on April 22.

Space & Earth / Space Exploration

created 17 hours ago | popularity 5 / 5 (2) | comments 0

10 million years needed to recover from mass extinction

(Phys.org) -- It took some 10 million years for Earth to recover from the greatest mass extinction of all time, latest research has revealed.

Space & Earth / Earth Sciences

created May 27, 2012 | popularity 4.4 / 5 (8) | comments 18 | with audio podcast

Hazelnuts: New source of key fat for infant formula that's more like mother's milk

Human breast milk is the best source of food for infants. University of Georgia researchers have found what may be a new second best—formula made from hazelnut oil.

Chemistry / Biochemistry

created May 23, 2012 | popularity 5 / 5 (1) | comments 0

Supercharged safflower

This scientific achievement has produced safflower seed oil that contains more than 90 per cent of this valuable fatty acid, the highest level of purity of an individual fatty acid currently available in any ...

Biology / Biotechnology

created May 21, 2012 | popularity not rated yet | comments 0

New details about gene regulation explained

(Phys.org) -- When genetic information is read from the genetic blueprint DNA, RNA polymerase II translates it into RNA molecules. The C-terminal domain, abbreviated as CTD, is an important area of the polymerase ...

Biology / Biotechnology

created May 21, 2012 | popularity not rated yet | comments 0 | with audio podcast

Friendly Fungi: Elucidating the fungal biosynthesis of stipitatic acid

(Phys.org) -- In a tale worthy of Sherlock Holmes, scientists in the School of Chemistry at the University of Bristol, UK have solved a biochemical mystery that had previously proven elusive for 70 years: ...

Biology / Biotechnology

created May 18, 2012 | popularity 3.7 / 5 (3) | comments 1 | with audio podcast feature

New research discovers metabolic adaptation to high altitudes

When mammals are cold, they can employ physical changes to stay warm -- such as intense shivering. Like any form of aerobic exercise, though, "shivering thermogenesis" is especially challenging at high altitudes ...

Biology / Plants & Animals

created May 17, 2012 | popularity 5 / 5 (1) | comments 0 | with audio podcast

Shining light on cells' inner workings

(Phys.org) -- Lanrong Bi and Nazmiye Yapici are shining new light on the hidden processes within cells. For their groundbreaking research, Bi, an assistant professor of chemistry at Michigan Technological ...

Chemistry / Biochemistry

created May 16, 2012 | popularity 5 / 5 (1) | comments 0 | with audio podcast

Scientists sound acid alarm for plankton

The microscopic organisms on which almost all life in the oceans depends could be even more vulnerable to increasingly acidic waters than scientists realised, according to a new study.

Space & Earth / Environment

created May 15, 2012 | popularity 4.2 / 5 (10) | comments 7 | with audio podcast

Study reveals how ribosomes override their blockades

Ribosomes are "protein factories" in the cells of all living things. They produce proteins based on existing genetic codes stored on special nucleic acid molecules. These molecules, also called messenger RNA (mRNA) due to ...

Biology / Cell & Microbiology

created May 14, 2012 | popularity 5 / 5 (1) | comments 0

Cellular secrets of plant fatty acid production understood; discovery could boost bioeconomy

(Phys.org) -- Research groups from Iowa State University and the Salk Institute for Biological Studies have uncovered the function of three plant proteins, a discovery that could help plant scientists boost ...

Biology / Biotechnology

created May 14, 2012 | popularity 5 / 5 (3) | comments 3 | with audio podcast

New screening technique yields elusive compounds to block immune-regulating enzyme

Scientists at The Scripps Research Institute have found the first chemical compounds that act to block an enzyme that has been linked to inflammatory conditions such as asthma and arthritis, as well as some ...

Chemistry / Biochemistry

created May 11, 2012 | popularity not rated yet | comments 0 | with audio podcast

Novel battery system could reduce buildings' electric bills

The CUNY Energy Institute, which has been developing innovative low-cost batteries that are safe, non-toxic, and reliable with fast discharge rates and high energy densities, announced that it has built an operating prototype ...

Technology / Energy & Green Tech

created May 08, 2012 | popularity 5 / 5 (10) | comments 14 | with audio podcast

Breeder works to reduce aluminum toxicity in rice

(Phys.org) -- As rice farmers around the world begin to turn from wet paddies to dry fields in an attempt to conserve water and mitigate climate change, they are facing a new foe: aluminum.

Biology / Biotechnology

created May 08, 2012 | popularity not rated yet | comments 0

Long-term monitoring shows 60 percent reduction in acidity of Delaware rain

Several decades ago, precipitation in Delaware was among the most acidic in the country. Pollutants in the air reacted with rainwater to sprinkle sulfuric, nitric and carbonic acids onto the ground below, ...

Space & Earth / Environment

created May 03, 2012 | popularity not rated yet | comments 2

Acid

An acid (from the Latin acidus/acēre meaning sour) is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red. Chemicals or substances having the property of an acid are said to be acidic.

Common examples of acids include acetic acid (in vinegar), sulfuric acid (used in car batteries), and tartaric acid (used in baking). As these three examples show, acids can be solutions, liquids, or solids. Gases such as hydrogen chloride can be acids as well. Strong acids and some concentrated weak acids are corrosive, but there are exceptions such as carboranes and boric acid.

There are three common definitions for acids: the Arrhenius definition, the Brønsted-Lowry definition, and the Lewis definition. The Arrhenius definition states that acids are substances which increase the concentration of hydronium ions (H3O+) in solution. The Brønsted-Lowry definition is an expansion: an acid is a substance which can act as a proton donor. Most acids encountered in everyday life are aqueous solutions, or can be dissolved in water, and these two definitions are most relevant. The reason why pHs of acids are less than 7 is that the concentration of hydronium ions is greater than 10−7 moles per liter. Since pH is defined as the negative logarithm of the concentration of hydronium ions, acids thus have pHs of less than 7. By the Brønsted-Lowry definition, any compound which can easily be deprotonated can be considered an acid. Examples include alcohols and amines which contain O-H or N-H fragments.

In chemistry, the Lewis definition of acidity is frequently encountered. Lewis acids are electron-pair acceptors. Examples of Lewis acids include all metal cations, and electron-deficient molecules such as boron trifluoride and aluminium trichloride. Hydronium ions are acids according to all three definitions. Interestingly, although alcohols and amines can be Brønsted-Lowry acids as mentioned above, they can also function as Lewis bases due to the lone pairs of electrons on their oxygen and nitrogen atoms.

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