first-order kinetics

first-order kinetics

a chemical reaction in which the rate of decrease in the number of molecules of a substrate is proportional to the concentration of substrate molecules remaining. In first-order reactions involving two substances, only one of the concentrations affects the rate. The rate of metabolism of most drugs follows the rule of first-order kinetics and is independent of the dose. Also called first-order reaction. See also kinetics.
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The Langmuir-Hinshelwood model mentioned equivalent to concern with the pseudo first-order kinetics of photocatalytic degradation of basic azo dyes [2].
Several researchers, however, have questioned the possibility of the presence of multiple, independent retention sites and stated that a gradual change in slope from one time increment to the next was prevalent, indicating a continual change in the apparent rate constant (kD and precluding the operation of strictly first-order kinetics for the entire course of reaction time (Jopony and Young 1987; Allen et al.
PME inactivation followed first-order kinetics with a residual PME activity of 15% at all pressure-temperature combinations used by the researchers.
First-order kinetics mandates on/off symmetry, which means that the change in V[O.
7), for the first-order kinetics a plot of ln(1-[alpha]) against t will yield a straight line, with a slop equal to -k.
If first-order kinetics is found to be an adequate approximation for this system, a conventional fit of concentration/time data then yields the pseudo-first-order rate coefficient for the process.
0]) versus time is observed for the composite microspheres catalyst, indicating that the reaction follows first-order kinetics.
Some of the physical simulations that obey first-order kinetics include the flow of gas through an orifice (Coffin, 1948; Kahn, 1957) or the flow of liquids through capillaries (Lemlich, 1954; Davenport, 1975; Erwin, 1992).
Characteristic times associated with air-exchange, advective transport, diffusive transport, and first-order kinetics are important for indoor-pollutant dynamics and affect the outcome of reactions.
It was pseudo first-order kinetics," he says, "so I could use the same type of math that is used to measure the rate of radioactive decay--the math used in carbon dating.
2] response to such tests demonstrates the lagged-linear behaviour characteristic of first-order kinetics, with the V[O.
Qing and co-workers used the first-order kinetics in their study on pyrolysis of Huadian oil shale since it resulted in best fit of experimental data [12].

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