Energy & Green Tech
In line with the fight against climate change and the search for a sustainable future, there is the idea of a future society based on hydrogen used as a fuel. This biofuel of the future could be what cars and engines run ...
Sep 16, 2019
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5
Energy & Green Tech
A common greenhouse gas could be repurposed in an efficient and environmentally friendly way with an electrolyzer that uses renewable electricity to produce pure liquid fuels.
Sep 3, 2019
3
3964
Machine learning & AI
Proteins are biological high-performance machines. They can be found in every cell and play an important role in human blood coagulation or as main constituents of hairs or muscles. The function of these molecular tools is ...
Aug 14, 2019
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65
Machine learning & AI
Next-generation sequencing technology has ushered in a new era in medicine, making it easier to identify a sequence of nucleotides in DNA or a sequence of amino acids in the proteins of a specific individual and use this ...
Aug 13, 2019
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25
Engineering
James Cook University scientists in Australia are using 3-D printing to create fuels for rockets, and using tailor-made rocket motors they've built to test the fuels.
Jul 30, 2019
0
3
Energy & Green Tech
A future powered by carbon-free fuel depends on our ability to harness and store energy from renewable but intermittent sources, such as solar and wind. Now, a new catalyst developed at University of Toronto Engineering gives ...
Dec 12, 2018
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430
Engineering
Its name is an acronym used to convey its size, but researchers at Cornell Engineering and Weill Cornell Medicine are hoping their hand-held cancer detection device's impact in the developing world is anything but small.
Sep 17, 2018
0
71
Energy & Green Tech
MSU scientists have a new proof of concept for a biofuel production platform that uses two species of marine algae and soil fungi. It lowers cultivation and harvesting costs and increases productivity, factors that currently ...
Sep 13, 2018
0
276
Engineering
A team of researchers from Tsinghua University working with People's Liberation Army Air Force General Hospital, both in China, has developed a two-stage patch that can be used to test glucose levels. In their paper published ...
Energy & Green Tech
In large parts of the developing world, people have abundant heat from the sun during the day, but most cooking takes place later in the evening when the sun is down, using fuel—such as wood, brush or dung—that is collected ...
Nov 17, 2017
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439
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
