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1、化学英语证书考试化学英语证书考试（PEC）常用词汇定义）常用词汇定义Absorbents - Absorbents are material that take up or absorb any liquids or vapors that come in contact with it.Acetyl - Any chemical compound with an acetate group.Acid - It is a water soluble sour tasting chemical compound. An acid has pH less than 7. The molecule
2、contains hydrogen and are sour tasting compounds and their generic formula is AH.Acidosis - Acid poisoning in the bloodAdditives - In the manufacturing process of plastics, polymer is just one constituent. There are other chemicals like impact modifiers, colorants, reinforcements, plasticisers and s
3、tabilizers etc that give specific properties to the plastics. These are called additives.Agrochemical - Chemicals, like hormone, fungicide, or insecticide, that improve or protects the crop production.Alcohols - Alcohol in chemistry means any organic compound in which a hydroxyl group (OH) is bound
4、to a carbon atom, further bound to other hydrogen and/or carbon atoms.Aldehyde - An important starting material and intermediate in organic synthesis. Many aldehydes of industrial significance are used as solvents, perfumes, and flavouring agents or as intermediates in the manufacture of plastics, d
5、yes, and pharmaceuticals.Aliphatic - Any organic compound in which the main structure is a chain of carbon atoms joined to each other. Alkali - A compound that has the ability to neutralize an acid to form a salt. A substance which is somewhat irritating or corrosive to the skin, eyes and mucous mem
6、branes. Turns red litmus paper to blue. Common strong alkalis are sodium and potassium hydroxide.Alkenes - Unsaturated hydrocarbons that contain one or more carbon-carbon double bonds. AllChemE - Alliance for Chemical Sciences and Technologies in Europe. The representative body for chemistry and che
7、mical engineering in Europe. Amines - Amines are organic compounds containing nitrogen. Here one or more hydrogen atoms are replaced by alkyl groups or other groups where the nitrogen is bonded to a carbon atom in the group. Amine are used in rubber, dyes, pharmaceuticals, and synthetic resins and f
8、ibres and in a host of other applications.Amorphous solid - A noncrystalline solid with no well-defined ordered structure.Anhydride - Any chemical compound obtained, either in practice or in principle, by the elimination of water from another compound.Aromatics - Aromatics, so called because of thei
9、r distinctive perfumed smell, are a group of hydrocarbons including, mainly, benzene, toluene and the xylenes. These are basic chemicals used as starting materials for a wide range of consumer products. Almost all aromatics come from crude oil, although small quantities are made from coal.Atom - Ato
10、m is the basic building block of chemistry. Atoms, also called chemical elements, can combine with one another to form compound. It is the smallest unit of matter that cannot be decomposed into simpler substances by ordinary chemical processes. Biocide - Biocides are formulations of one or more acti
11、ve substances which can kill or control viruses, bacteria, algae, moulds or yeasts.Burden of the Past - The 30,000 Existing Chemicals estimated to be on the EU market, for which little or no information is available, in particular about their long-term effects on human health or the environment.CAS
12、number - Chemical Abstracts System number; CAS is the producer of the worlds largest and most comprehensive databases of chemical information. It is a division of the American Chemical Society. Catalyst - A substance which aids or promotes a chemical reaction without forming part of the final produc
13、t.Catalytic cracking - The process of breaking up heavier hydrocarbon molecules into lighter hydrocarbon fractions by use of heat and catalysts. Category - A group of closely related chemicals whose physico-chemical, ecotoxicological or toxicological properties follow a regular pattern because of st
14、ructural similarity.Chemical Reaction - A chemical process in which substances are changed into different substances with different properties. Colloid - Colloidal systems are stable dispersions of microscopic solid particles.Composite - A solid material made of two or more different substances, com
15、bined to produce a new substance whose properties are superior to the original components in a specific application. Compound - A compound (or molecule) is a combination of two or more different chemical elements (atoms) held together by chemical bonds.Contaminant - An impurity not intended to be pr
16、esent in the product that may be introduced through such things as poor cleaning, processing, lack of appropriate environmental and personnel controls during the manufacturing process, handling and distribution.Centrifugal Compressor - A centrifugal compressor compresses air or gas by means of mechanical rotating rotating vanes or impellers.Chemical Recycling - Chemical recycling is the process of recycling waste products by partially altering their chemical
