الرئيسية » Simplified Chemistry (صفحه 9)

Simplified Chemistry

Alicyclic hydrocarbon

An organic compound that contains one or more closed rings of carbon atoms. The term alicyclic specifically excludes carbocyclic com­pounds with an array of n-electrons characteristic of aromatic rings. Compounds with one to five alicyclic rings of great variety and complexity are found in many natural products such as steroids.and …

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aldehydes

One of a class of organic chemical compounds represented by the general formula RCHO. Formaldehyde, the simplest aldehyde, has the formula HCHO, where R is hydrogen. For all other aldehydes, R is a hydrocarbon radical which may be substituted with other groups such as halogen or hydroxyl (see table). Because …

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Alcohol

A member of a class of organic compounds composed of carbon, hydro­gen, and oxygen. They can be considered as hydroxyl derivatives of hydrocarbons produced by the replacement of one or more hydrogens by one or more hydroxyl (R-OH) groups. Classification. Alcohols may be mono-, di-, tri-, or polyhydric, depending upon …

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Aerosol

A suspension of small particles in a gas. The particles may be solid or liquid or a mixture of both. Aerosols are formed by the conversion of gases to particles, the disintegration of liquids or solids, or the resuspension of powdered material. Aerosol formation from a gas results in much …

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Adsorption

A process in which atoms or molecules move from a bulk phase (that is, solid, liquid, or gas) onto a solid or liquid surface. An example is purification by adsorption where impurities are filtered from liquids or gases by their adsorption onto the surface of a high-surface-area solid such as …

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adhesive

A material capable of fastening two other materials together by means of surface attachment. The terms glue, mucilage, mastic, and cement are synonymous with adhesive. In a generic sense, the word adhesive implies any material capable of fastening by surface attachment, and thus will include inorganic materials such as portland …

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Adsorption

A process in which atoms or molecules move from a bulk phase (that is, solid, liquid, or gas) onto a solid or liquid surface. An example is purification by adsorption where impurities are filtered from liquids or gases by their adsorption onto the surface of a high-surface-area solid such as …

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Adhesive

A material capable of fastening two other materials together by means of surface attachment. The terms glue, mucilage, mastic, and cement are synonymous with adhesive. In a generic sense, the word adhesive implies any material capable of fastening by surface attachment, and thus will include inorganic materials such as portland …

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acylation

A process in which a hydrogen atom in an organic compound is re­placed by an acyl group (R-CO, where R = an organic group). The reaction in­volves substitution by a nucleophile (electron donor) at the electrophilic carbonyl group (C=O) of a carboxylic acid derivative. The substitution usually proceeds by an …

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Activation analysis

A technique in which a neutron, charged particle, or gamma photon is captured by a stable nuclide to produce a different, radioactive nu­clide which is then measured. The technique is specific, highly sensitive, and applicable to almost every element in the periodic table. In neutron activation analysis (NAA), the most …

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