An international collaboration led by scientists at Tokyo University of Agriculture and Technology (TUAT) , Japan, has developed a two-step method to more efficiently break down carbohydrates into their single sugar components, ...
Materials Science
Jun 14, 2019
0
7
Microbiologists of St Petersburg University, together with researchers from the University of Milan, the University of Pisa, and the University of Pavia, have discovered a new family of bacteria of the order Rickettsiales—Deianiraeaceae. ...
Cell & Microbiology
Jun 14, 2019
0
10
Scientists in Japan have developed a way of amplifying DNA on a scale suitable for use in the emerging fields of DNA-based computing and molecular robotics. By enabling highly sensitive nucleic acid detection, their method ...
Biochemistry
Jun 14, 2019
0
7
Europa, a frozen moon around Jupiter, is believed to be one of the most habitable worlds in the solar system. It was first imaged in detail by the Voyager 1 probe in 1979, revealing a surface almost devoid of large craters. ...
Space Exploration
Jun 14, 2019
0
45
UMBC's Hua Lu, professor of biological sciences, and colleagues have found new genetic links between a plant's circadian rhythm (essentially, an internal clock) and its ability to fend off diseases and pests. The findings ...
Biotechnology
Jun 12, 2019
0
91
Biorefinery technology uses biomass as a feedstock and converts it to energy and other beneficial byproducts. It is drawing attention as an eco-friendly and sustainable technology to prepare for depletion of fossil fuels. ...
Biotechnology
Jun 11, 2019
0
4
A research group from Ruhr-Universität Bochum has investigated how acids interact with water molecules at extremely low temperatures. Using spectroscopic analyses and computer simulations, they investigated the question ...
Materials Science
Jun 10, 2019
0
471
NUS food scientists have found that a combination of lactic acid with food grade sodium hypochlorite is an effective sanitizer to process fresh organic vegetables.
Plants & Animals
Jun 07, 2019
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4
Scientists often build new protein molecules by stringing groups of amino acids together. These amino acid chains, called polypeptides, are the building blocks needed in drug development and the creation of new biomaterials.
Biochemistry
Jun 06, 2019
0
19
An international team of researchers recently synthesized polyarylether-based covalent organic frameworks, the most stable crystalline porous material on record. The team, which includes the University of Delaware's Yushan ...
Materials Science
Jun 06, 2019
0
54
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.
This text uses material from Wikipedia, licensed under CC BY-SA
