Chemical substance

A chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e., without breaking chemical bonds. Chemical substances can be chemical elements, chemical compounds, ions or alloys.

Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. Other chemical substances commonly encountered in pure form are diamond (carbon), gold, table salt (sodium chloride) and refined sugar (sucrose). However, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical.

Chemical substances exist as solids, liquids, gases or plasma, and may change between these phases of matter with changes in temperature or pressure. Chemical reactions convert one chemical substance into another.

Chemistry

Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter. Chemistry includes topics such as the properties of individual atoms, how atoms form chemical bonds to create chemical compounds, the interactions of substances through intermolecular forces that give matter its general properties, and the interactions between substances through chemical reactions to form different substances.

Chemistry is sometimes called the central science because it bridges other natural sciences, including physics, geology and biology. For the differences between chemistry and physics see Comparison of chemistry and physics.

Scholars disagree about the etymology of the word chemistry. The history of chemistry can be traced to alchemy, which had been practiced for several millennia in various parts of the world.

Etymology

The word chemistry comes from the word alchemy which was an earlier set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism and medicine. It is often seen as linked to the quest to turn lead or another common starting material into gold. Alchemy, which was practiced around 330, is the study of the composition of waters, movement, growth, embodying, disembodying, drawing the spirits from bodies and bonding the spirits within bodies (Zosimos). 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".

Chemical (Crashdïet song)

Chemical is the second single from the Swedish glam metal band Crashdïet's 2010 album Generation Wild. It was released on 19 September and was written by Crashdïet's guitarist Martin Sweet and the band Peep Show's singer Johnny Gunn.

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Lovers (Dufresne album)

Lovers is the second album by Italian post-hardcore band Dufresne. It was released April 11, 2008.

The album was recorded in October, 2007 in Richmond, Virginia at Red Planet Studios, produced by Andreas Magnusson.

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Lovers (David Murray album)

Lovers is an album by David Murray released on the Japanese DIW label. It was released in 1988 and features six quartet performances by Murray with Fred Hopkins, Dave Burrell and Ralph Peterson Jr..

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Lovers (Cannonball Adderley album)

Lovers is an album by jazz saxophonist Cannonball Adderley recorded at the Fantasy Studios in Berkeley, California in 1975, featuring the last recorded performances by Adderley with Nat Adderley, Alvin Batiste, George Duke, Alphonso Johnson, Jack DeJohnette, Airto Moreira with a posthumous track featuring Flora Purim, Nat Adderley, Jr. and Ron Carter.

Reception

The Allmusic review by Scott Yanow awarded the album 1½ stars and states: "This particular LP was already more than half completed with Adderley taking his last solos on three of the selections... but unfortunately none of the music is all that memorable.... After Cannonball's death 'Lovers' (which had been planned for the album) was recorded as a memorial.... The intentions were honorable but the music is pretty forgettable."

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