The evaluation of rate constants in rate laws containing two terms

Abstract

A simple computerized method using APL is described which gives the rate constants for

The reaction of ozone with thiophene in the gas phase

“…The value of k , is unaffected by added 0 2 as seen in Figure 6, but k2 is drastically reduced by even small amounts of added 02, as Figure 7 shows. The inhibiting effect of O2 on kz has been found in the reaction of ozone with allene [8], l,&butadiene [8], ethylene [9], propene [lo], and tetrafluorolsthene [7], but not with hydrogen sulfide [ll] where the chain carriers evidently do not react with 02. We studied the effect of added 0 2 over a somewhat larger range than previously [8,9], and Figure 7 shows that the limit of kz is probably not zero.…”

“…The inhibiting effect of O2 on kz has been found in the reaction of ozone with allene [8], l,&butadiene [8], ethylene [9], propene [lo], and tetrafluorolsthene [7], but not with hydrogen sulfide [ll] where the chain carriers evidently do not react with 02. We studied the effect of added 0 2 over a somewhat larger range than previously [8,9], and Figure 7 shows that the limit of kz is probably not zero. The importance of this result is that it casts doubt on the assumption that one can measure primary rate constants of ozone reactions by simply measuring the overall rate of O3 disappearance in the presence of 0 2 .…”

Noniterative microcomputer analysis of competing first- and m-order reactions by a constant time interval method

“…Analytes which can be deposited in a thin layer on suitable substrates can meet these requirements. Preconcentration has been accomplished through the use of ion-exchange resin-loaded filter papers (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), or by coprecipitation of the analyte elements with chelating agents followed by collection on membrane filters (13-16). Campbell et al (1) first characterized ion-exchange resin-loaded filter papers for preconcentrating microgram quantities of cations and anions for X-ray fluorescence analysis.…”

“…As pointed out by Toby (1), the rate law for a complex reaction between two chemical species A and B, especially in chain reaction, can frequently be written -d[A]/di = kdA][B] + UAHBp (1) where m and p are Usually integral or half-integral. Since kinetic studies are usually performed with an excess of one of the reactants, eq 1 can be written as eq 2, where k\ and km' are pseudoconstants including the concentrations of B.…”

“…-d[A]/df = MA] + km\AT (2) The two most common ways of solving eq 2 for and km' are by graph (2) (by plotting (-d[A]/di)/ [A] vs. [A]"*""1) or via iterative minimization of the difference between what is actually observed and what is predicted (3). Recently, Toby (1) suggested that fci'and km'be calculated from the following form of the integrated equation (eq 3) where K is the ratio ^mV^i'and n = m -1 ([A]0 is concentration at zero time).…”