Thursday, November 8, 2012


Chemistry

From Wikipedia, the free encyclopedia

Chemicals in flasks (including Ammonium hydroxide and Nitric acid) lit in different colors
Chemistry, a branch of physical science is the study of the composition, properties and behavior of matter.[1][2] Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds. Chemistry is also concerned with the interactions between atoms (or groups of atoms) and various forms of energy (e.g. photochemical reactions, changes in phases of matter, separation of mixtures, properties of polymers, etc.).
Chemistry is sometimes called "the central science" because it connects physics with other natural sciences such as geology and biology.[3][4] Chemistry is a branch of physical science but distinct from physics.[5]
The etymology of the word chemistry has been much disputed.[6] The genesis of chemistry can be traced to certain practices, known as alchemy, which had been practiced for several millennia in various parts of the world, particularly the Middle East.[7]

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Etymology

The word chemistry comes from the word alchemy, an earlier set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism and medicine; it is commonly thought of as the quest to turn lead or another common starting material into gold.[8] The word alchemyin turn is derived from the Arabic word al-kīmīā (الكيمياء). The Arabic term is borrowed from the Greek χημία or χημεία.[9][10] This may have Egyptianorigins. Many believe that al-kīmīā is derived from χημία, which is in turn derived from the word Chemi or Kimi, which is the ancient name of Egypt inEgyptian.[9] Alternately, al-kīmīā may be derived from χημεία, meaning "cast together".[11]
An alchemist was called a 'chemist' in popular speech, and later the suffix "-ry" was added to this to describe the art of the chemist as "chemistry".

Saturday, October 13, 2012

Ion


What is an ion?

An ion is a charged atom or molecule. It is charged because the number of electrons do not equal the number of protons in the atom or molecule. An atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.
When an atom is attracted to another atom because it has an unequal number of electrons and protons, the atom is called an ION. If the atom has more electrons than protons, it is a negative ion, or ANION. If it has more protons than electrons,it is a positive ion.

Molecule


Molecule

From Wikipedia, the free encyclopedia
3D (left and center) and 2D (right) representations of the terpenoidmolecule atisane
molecule (play /ˈmɒlɪkjuːl/) is an electrically neutral group of two or more atoms held together by covalentchemical bonds.[1][2][3][4][5][6] Molecules are distinguished from ions by their lack of electrical charge. However, in quantum physicsorganic chemistry, andbiochemistry, the term molecule is often used less strictly, also being applied to polyatomic ions.
In the kinetic theory of gases, the term molecule is often used for any gaseous particle regardless of its composition. According to this definition noble gasatoms are considered molecules despite the fact that they are composed of a single non-bonded atom.[7]
A molecule may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water(H2O). Atoms and complexes connected by non-covalent bonds such as hydrogen bonds or ionic bonds are generally not considered single molecules.[8]
Molecules as components of matter are common in organic substances (and therefore biochemistry). They also make up most of the oceans and atmosphere. However, the majority of familiar solid substances on Earth, including most of the minerals that make up the crustmantle, and core of the Earth, contain many chemical bonds, but are not made of identifiable molecules. Also, no typical molecule can be defined for ionic crystals (salts) and covalent crystals (network solids), although these are often composed of repeating unit cells that extend either in a plane (such as in graphene) or three-dimensionally (such as in diamondquartz, or sodium chloride). The theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding, which means that solid metals are also not made of molecules. In glasses (solids that exist in a vitreous disordered state), atoms may also be held together by chemical bonds without presence of any definable molecule, but also without any of the regularity of repeating units that characterises crystals.

Atom



Atom (standard)


 The name Atom applies to a pair of related standards. The Atom Syndication Formatis an XML language used for web feeds, while the Atom Publishing Protocol(AtomPub or APP) is a simple HTTP-based protocol for creating and updating web resources.
Web feeds allow software programs to check for updates published on a website. To provide a web feed, a site owner may use specialized software (such as acontent management system) that publishes a list (or "feed") of recent articles or content in a standardized, machine-readable format. The feed can then be downloaded by programs that use it, like websites that syndicate content from the feed, or by feed reader programs that allow Internet users to subscribe to feeds and view their content.
A feed contains entries, which may be headlines, full-text articles, excerpts, summaries, and/or links to content on a website, along with various metadata.
The Atom format was developed as an alternative to RSSBen Trott, an advocate of the new format that became Atom, believed that RSS had limitations and flaws—such as lack of on-going innovation and its necessity to remain backward compatible— and that there were advantages to a fresh design.[1]
Proponents of the new format formed the IETF Atom Publishing Format and Protocol Workgroup. The Atom syndication format was published as an IETF proposed standard in RFC 4287 (December 2005), and the Atom Publishing Protocol was published as RFC 5023 (October 2007).

Thursday, October 11, 2012

EuygunS

My biodata:

Name:Euygun Sin
Age:14
Adress:Legenda Wisata,Cibubur
Hobby:Playing games,soccer,guitar,etc