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(physical chemistry)
The numerical relationship of elements and compounds as reactants and products in chemical reactions.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



in chemistry, the study of the quantitative relationships between the weights (volumes) of reacting substances. Stoichiometry includes the derivation of chemical formulas and chemical equations, and its principles are used in the calculations of chemical analysis. The term “stoichiometry” was introduced by J. Richter in his book Anfangsgründe der Stöchiometrie (vols. 1–3, 1792–94), in which he synthesized the results of his determinations of the weights of acids and bases during the formation of salts.

The major postulates of stoichiometry are derived from Avo- gadro’s law, Gay-Lussac’s law of combining volumes, the law of multiple proportions, the law of definite proportions, the principle of the conservation of mass, and the law of equivalent proportions. The rules of stoichiometry govern all calculations related to chemical equations. Stoichiometric calculations are widely used in chemical engineering and metallurgy.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Although the induction period is short, the process might still be governing the energetics of the reaction even during the exchange period resulting in the constant energy being observed up to extent of reaction of 0.5.
In the case of the extent of reaction, a guess is used that presents a maximum rate within a determined stage and a quadratic rate fall of the same up to the extreme reactive stages (first and last reaction stages).
The same FDEMS sensor was later attached to a steel pipe for insertion into the pilot plant's reactor for monitoring production batches based on the calibration of the sensor output with extent of reaction from the laboratory experiments.
where [T.sub.g0] and [T.sub.g[infinity]] are [T.sub.g]s at zero extent of reaction and complete reaction, respectively, while x and [lambda] are extent of reaction and adjustable parameter, respectively.
The areas of the peak at various times under the isothermal curve were used to calculate the extent of reaction. The extent of reaction, x, at time t, was defined as:
The initial rate of increase of the extent of reaction in the range of 0 to 700 s (represented by an increase in moduli) is higher at 300[degrees]C than at 270[degrees]C: this confirms similar observations from batch mixer data reported in our earlier publication (5).
The definition of gel point is the time or the extent of reaction of monomers at which a three-dimensional network is formed at the macro scale throughout the resin.
The objective is to correlate ultrasonic velocity to extent of reaction based on the model experiments of poly(methyl methacrylate) in solution with MMA.
The effects of various processing conditions in a batch mixer and a single-screw extruder on the extent of reaction were assessed.
The extent of reaction is calculated from NIR absorption band at 4530 [cm.sup.-1], which depends on epoxide concentration.
The extent of reaction [alpha] is represented as a function of the reaction time in the insert to Fig.