Acid
An acid (from the Latin acidus/acēre meaning sour) is a chemical substance whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals (like calcium) to form salts. An aqueous solution of an acid has a pH of less than 7 and is colloquially also referred to as 'acid' (as in 'dissolved in acid'), while the strict definition refers only to the solute. An acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H+ (a positive hydrogen ion or proton). A lower pH means a higher acidity, and thus a higher concentration of positive hydrogen ions in the solution. Chemicals or substances having the property of an acid are said to be acidic.
There are three common definitions for acids: the Arrhenius definition, the Brønsted-Lowry definition, and the Lewis definition. The Arrhenius definition defines acids as substances which increase the concentration of hydrogen ions (H+), or more accurately, hydronium ions (H3O+), when dissolved in water. The Brønsted-Lowry definition is an expansion to include solvents other than water: an acid is a substance which can act as a proton donor. By this definition, any compound which can be deprotonated can be considered an acid. Examples include alcohols and amines which contain O-H or N-H fragments. A Lewis acid is a substance that can accept a pair of electrons to form a covalent bond. Examples of Lewis acids include all metal cations, and electron-deficient molecules such as boron trifluoride and aluminium trichloride.
Acids in wine
The acids in wine are an important component in both winemaking and the finished product of wine. They are present in both grapes and wine, having direct influences on the color, balance and taste of the wine as well as the growth and vitality of yeast during fermentation and protecting the wine from bacteria. The measure of the amount of acidity in wine is known as the “titratable acidity” or “total acidity”, which refers to the test that yields the total of all acids present, while strength of acidity is measured according to pH, with most wines having a pH between 2.9 and 3.9. Generally, the lower the pH, the higher the acidity in the wine. However, there is no direct connection between total acidity and pH (it is possible to find wines with a high pH for wine and high acidity). In wine tasting, the term “acidity” refers to the fresh, tart and sour attributes of the wine which are evaluated in relation to how well the acidity balances out the sweetness and bitter components of the wine such as tannins. Three primary acids are found in wine grapes: tartaric, malic and citric acids. During the course of winemaking and in the finished wines, acetic, butyric, lactic and succinic acids can play significant roles. Most of the acids involved with wine are fixed acids with the notable exception of acetic acid, mostly found in vinegar, which is volatile and can contribute to the wine fault known as volatile acidity. Sometimes, additional acids, such as ascorbic, sorbic and sulfurous acids, are used in winemaking.
Acid (disambiguation)
An acid is any chemical compound that, when dissolved in water, gives a solution with a pH less than 7.0.
Acid or ACID may also refer to:
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Daniel Rosenfeld
Daniel Rosenfeld (born May 9, 1989) is a German musician and sound engineer best known as the composer and sound designer for the computer game Minecraft. His music is generally published under the name C418 (pronounced "see-four-eighteen").
Rosenfeld was born and grew up in East Germany after reunification, and the economic realities of the region limited his resources to learn audio composition . He says he learned on early versions of Schism Tracker and Ableton Live in the early 2000s, which were both rudimentary tools at the time. Learning under such restrictions turned out to help the young composer when he began collaborating with Minecraft creator Markus "Notch" Persson. The sound engine in the game was not very powerful, so Rosenfeld had to be creative in his approach to sound effects and music.
As a freelance artist, Rosenfeld was not on staff at Mojang, the game company behind Minecraft, which was sold to Microsoft in 2014. Rosenfeld says he still owns the rights to all the music in the game, having released two albums featuring songs from the soundtrack. The first soundtrack, Minecraft - Volume Alpha, was released on March 4, 2011. The video game blog Kotaku selected the music of Minecraft as one of the best video game soundtracks of 2011. On November 9, 2013, Rosenfeld released the second official soundtrack, titled Minecraft - Volume Beta, which includes the music that was added in later versions of the game.Minecraft - Volume Alpha found its first release in physical format on Ghostly International in 2015.
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