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alkyl group
alkyl group , in chemistry, group of carbon and hydrogen atoms derived from an alkane molecule by removing one hydrogen atom (see radical ). The name of the alkyl group is derived from the name of its alkane by replacing the - ane suffix with - yl, e.g., methyl, CH 3 , from methane, CH 4 , and ...
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hydroxyl group
hydroxyl group , in chemistry, functional group that consists of an oxygen atom joined by a single bond to a hydrogen atom. An alcohol is formed when a hydroxyl group is joined by a single bond to an alkyl group or aryl group . A metal hydroxide is formed when a hydroxyl group is joined to a ...
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alcohol
alcohol any of a class of organic compounds with the general formula R-OH, where R represents an alkyl group made up of carbon and hydrogen in various proportions and -OH represents one or more hydroxyl groups . In common usage the term alcohol usually refers to ethanol . The class of alcohols ...
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totem
totem , an object, usually an animal or plant (or all animals or plants of that species), that is revered by members of a particular social group because of a mystical or ritual relationship that exists with that group. The totem—or rather, the spirit it embodies—represents the bond of u...
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carboxyl group
carboxyl group , in chemistry, functional group that consists of a carbon atom joined to an oxygen atom by a double bond and to a hydroxyl group , OH, by a single bond. Carboxylic acids are compounds whose molecules contain a carboxyl group that is joined to a hydrogen atom, an alkyl group , or ...
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streptococcus
streptococcus , any of a group of gram-positive bacteria, genus Streptococcus, some of which cause disease. Streptococci are spherical and divide by fission, but they remain attached and so grow in beadlike chains. The incidence and severity of streptococcal diseases decreased dramatically after t...
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benzoic acid
benzoic acid , C 6 H 5 CO 2 H, crystalline solid organic acid that melts at 122°C and boils at 249°C. It is the simplest aromatic carboxylic acid (see aryl group and carboxyl group ). In addition to being synthesized from a variety of organic compounds (e.g., benzyl alcohol, benzaldehyde,...
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vinyl plastics
vinyl plastics group of thermoplastics used in molded products, flexible tubing, material for raincoats, and laminated safety glass. Vinyl plastics are polymers and copolymers of vinyl derivatives (i.e., derivatives of ethylene, H 2 C[symbol]CH 2 ), e.g., vinyl chloride (H 2 C=CHCl) and vinyl a...
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self-help group
self-help group nonprofessional organization formed by people with a common problem or situation, for the purpose of pooling resources, gathering information, and offering mutual support, services, or care. Self-help groups began to spread in the United States following World War II and proliferate...
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local group
LOCAL GROUP
[local group]
in astronomy, loose cluster of at least 19 nearby galaxies , including our own Milky Way galaxy, the Andromeda Galaxy , and the Magellanic Clouds . The local group is spread over an ellipsoidal region of space with a major axis of approximately 3 million light-ye...
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