Search results
Results From The WOW.Com Content Network
For very thin materials, the surface area remains relatively constant when the material degrades, which allows surface erosion to be characterized as zero order release since the rate of degradation is constant. [2] [3] In bulk erosion, the erosion rate depends on the volume of the material. [3]
where A and B are reactants C is a product a, b, and c are stoichiometric coefficients,. the reaction rate is often found to have the form: = [] [] Here is the reaction rate constant that depends on temperature, and [A] and [B] are the molar concentrations of substances A and B in moles per unit volume of solution, assuming the reaction is taking place throughout the volume of the ...
In physical chemistry, the Arrhenius equation is a formula for the temperature dependence of reaction rates.The equation was proposed by Svante Arrhenius in 1889, based on the work of Dutch chemist Jacobus Henricus van 't Hoff who had noted in 1884 that the van 't Hoff equation for the temperature dependence of equilibrium constants suggests such a formula for the rates of both forward and ...
is the rate constant for surface adsorption, m 3 ·mol −1 ·s −1 k − 1 {\displaystyle k_{-1}} is the rate constant for surface desorption, s −1 C S {\displaystyle C_{\mathrm {S} }} is highly related to the total surface area of the adsorbent: the greater the surface area, the more sites and the faster the reaction.
A quantity undergoing exponential decay. Larger decay constants make the quantity vanish much more rapidly. This plot shows decay for decay constant (λ) of 25, 5, 1, 1/5, and 1/25 for x from 0 to 5. A quantity is subject to exponential decay if it decreases at a rate proportional to its current value.
In chemistry, the rate equation (also known as the rate law or empirical differential rate equation) is an empirical differential mathematical expression for the reaction rate of a given reaction in terms of concentrations of chemical species and constant parameters (normally rate coefficients and partial orders of reaction) only. [1]
Half-life (symbol t ½) is the time required for a quantity (of substance) to reduce to half of its initial value.The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive.
In consequence, the reaction rate constant increases rapidly with temperature , as shown in the direct plot of against . (Mathematically, at very high temperatures so that E a ≪ R T {\displaystyle E_{\text{a}}\ll RT} , k {\displaystyle k} would level off and approach A {\displaystyle A} as a limit, but this case does not occur under practical ...