Stoichiometry

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stoichiometry

[‚stȯi·kē′äm·ə·trē]
(physical chemistry)
The numerical relationship of elements and compounds as reactants and products in chemical reactions.

Stoichiometry

 

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.

References in periodicals archive ?
Even though the way reflectance evolves can be different depending on the wavelength range, the important reflectance variation between 363 K (90[degrees]C) and 413 K (140[degrees]C) is related to the beginning of the reticulation, as the extent of reaction varies from 0.
g]s at zero extent of reaction and complete reaction, respectively, while x and [lambda] are extent of reaction and adjustable parameter, respectively.
Hardener(s)/DGEBA solutions are prepared at 135[degrees]C in a small reactor with a classical stirring for five minutes in order to keep the extent of reaction under 2% [20].
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).
In these processes, immediate and continuous information on the extent of reaction and material properties are required for proper control of the process.
in region 2, the extent of reaction depended only on the total strain applied to the melt, but much more strain energy was expended to initiate the chemical reaction at the higher rotor speed.
So, a direct comparison of the extent of reaction at ll0[degrees]C and 120[degrees]C for 110 min was measured by NIR spectra (18).
This suggests that the Kevlar fibers have a catalytic effect on the reaction since the maximum of the reaction rate and in general the whole DSC trace is shifted towards much shorter reaction times, as happens with the extent of reaction curve.
As a consequence, in the last decade, understanding of the cure process better has become of foremost importance for thermoset manufacturers in order to optimize cure cycles, Microdielectrometry seems to be a promising technique for obtaining on-line real-time data [3] in relation to thermoset properties such as the cure extent of reaction.
The extent of reaction, measured by the depression in equilibrium melting temperature, was linear with respect to the annealing time.
Microdielectrometry can be used to record in situ the extent of reaction of the epoxy reactive system for thin layers during radiant heating.
The extent of reaction achieved, the tridimensional network structure, the orientation of molecular segments along preferred directions all can affect the macroscopically measured properties.