heat of combustion
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heat of combustion,heatheat,
nonmechanical energy in transit, associated with differences in temperature between a system and its surroundings or between parts of the same system. Measures of Heat
..... Click the link for more information. released during combustioncombustion,
rapid chemical reaction of two or more substances with a characteristic liberation of heat and light; it is commonly called burning. The burning of a fuel (e.g., wood, coal, oil, or natural gas) in air is a familiar example of combustion.
..... Click the link for more information. . In particular, it is the amount of heat released when a given amount (usually 1 molemole,
in chemistry, a quantity of particles of any type equal to Avogadro's number, or 6.02×1023 particles. One gram-molecular weight of any molecular substance contains exactly one mole of molecules.
..... Click the link for more information. ) of a combustible pure substance is burned to form incombustible products (e.g., water and carbon dioxide); this amount of heat is a characteristic of the substance. Heats of combustion are used as a basis for comparing the heating value of fuels, since the fuel that produces the greater amount of heat for a given cost is the more economic. Heats of combustion are also used in comparing the stabilities of chemical compounds. For example, if equal quantities of two isomeric hydrocarbons burn to produce equal amounts of carbon dioxide and water, the one releasing more energy (i.e., with the higher heat of combustion) is the less stable, since it was the more energetic in its compounded form.
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heat of combustion[′hēt əv kəm′bəs·chən]
The amount of heat released in the oxidation of 1 mole of a substance at constant pressure, or constant volume. Also known as heat value; heating value.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.