first-order reaction

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first-·or·der re·ac·tion

a reaction in which the rate is proportional to the concentration of the single substance undergoing change; radioactive decay is a first-order process, defined by the equation dN/dt = kN, where N is the number of atoms subject to decay (reaction), t is time, and k is the first-order decay (reaction) constant, that is, the fraction of all atoms decaying per unit of time.
See also: decay constant, order.

first-order reaction

a reaction in which the rate of reaction is directly proportional to the concentration of one of the reactants, either product or substrate.
References in periodicals archive ?
2]) vs 1/Tm depicted in Figure 6 shows that the reaction of oil shale pyrolysis can be described by a first-order reaction model in the studied temperature range.
This makes it possible to apply the first-order reaction rate model used in peroxide crosslinking simulations to rubber curing.
Kinetic data for charcoal can only be fitted to a single first-order reaction, and all sorbed Ag can be desorbed at t = [infinity].
When assuming that oil shale pyrolysis is the first-order reaction, the rate of kerogen decomposition is given by:
Good agreement has been found as well in modeling it as two sequential, first-order reactions [19].
Several researchers have studied decomposition kinetics of oil shale pyrolysis; most of them have used the first-order reaction kinetics to model isothermal and non-isothermal kinetic data [21-25].
Although there were many RE analysis made for oil shale, the kinetic model was almost the first-order reaction.
Therefore, the degradation of PS is in proportion to the degree of polymerization, and the mechanochemical degradation of PS in the pan-mill type equipment is a first-order reaction.
Decomposition of oil shale kerogen in terms of a first-order reaction appears to be a suitable assumption since the value of n = 1 offers the best-fit regression line.

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