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Page "Nucleophilic substitution" ¶ 12
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reaction and rate
The rate of the gas phase exchange reaction appears to be proportional to the first power of the absorbed light intensity indicating that the radical intermediates are removed at the walls or by reaction with an impurity rather than by bimolecular radical combination reactions.
-- Although there was some variation in results which must be attributed either to trace impurities or to variation in wall effects, the photochemical exchange in the gas phase was sufficiently reproducible so that it seemed meaningful to compare the reaction rates in different series of reaction tubes for the purpose of obtaining information on the effect of chlorine concentration and of carbon tetrachloride concentration on the reaction rate.
Seeing a sublime view of a landscape may give us a reaction of awe, which might manifest physically as an increased heart rate or widened eyes.
By lowering the activation energy, the enzyme speeds up that reaction by a rate of 10 < sup > 11 </ sup > or more: a reaction that would normally take over 3, 000 years to complete spontaneously might take less than a second with an enzyme.
Usually, this state results when the forward reaction proceeds at the same rate as the reverse reaction.
However, the law of mass action is valid only for concerted one-step reactions that proceed through a single transition state and is not valid in general because rate equations do not, in general, follow the stoichiometry of the reaction as Guldberg and Waage had proposed ( see, for example, nucleophilic aliphatic substitution by S < sub > N </ sub > 1 or reaction of hydrogen and bromine to form hydrogen bromide ).
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst.
Catalytic reactions have a lower rate-limiting free energy of activation than the corresponding uncatalyzed reaction, resulting in higher reaction rate at the same temperature.
Kinetically, catalytic reactions are typical chemical reactions ; i. e. the reaction rate depends on the frequency of contact of the reactants in the rate-determining step.
The rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.
As a catalyst is regenerated in a reaction, often only small amounts are needed to increase the rate of the reaction.
The catalyst may increase reaction rate or selectivity, or enable the reaction at lower temperatures.
In the catalyzed elementary reaction, catalysts do not change the extent of a reaction: they have no effect on the chemical equilibrium of a reaction because the rate of both the forward and the reverse reaction are both affected ( see also thermodynamics ).

reaction and is
The response of reaction is dominated by a concern for what is vanishing.
The most reaction can achieve is stasis, and a stasis that can be maintained only by the expenditure of an effort which ultimately exhausts itself.
Since a civilizational crisis involves also a crisis in private interests and in the ruling class, reaction is normally found among those who feel themselves to be among the ruling class.
When the reactionary response is thus bolstered by an intellectual defense, the characteristics of that defense are explicable only in terms of the basic attitudes of unanalyzed reaction.
It is a Whig history of the `` Tory reaction '' which preceded the Reform Bill of 1832, and it uses the figure of Grey to give some unity to the narrative.
Representatives of Harvard University Press, which is publishing the book this month of April, recognize and freely acknowledge that they invited such reaction by allowing Life magazine to print an excerpt from the book in advance of the book's publication date.
This latter reaction is in accord with the reported decomposition of Af.
The small reaction occurring at 337-degrees-C is probably caused by decomposition of occluded nitrates, and perhaps by a small amount of some hydrous material other than Af.
He showed convincingly that anxiety is a learned ( conditioned ) reaction and is the basis of experimental and clinical neuroses and assumed, therefore, that the neuronal changes which underlie the neuroses are functional and reversible.
Autosuggestibility, the reaction of the subject in such a way as to conform to his own expectations of the outcome ( i.e., that the arm-rise is a reaction to the pressure exerted in the voluntary contraction, because of his knowledge that `` to every reaction there is an equal and opposite reaction '' ) also seems inadequate as an explanation for the following reasons: ( 1 ) the subjects' apparently genuine experience of surprise when their arms rose, and ( 2 ) manifestations of the phenomenon despite anticipations of something else happening ( e.g., of becoming dizzy and maybe falling, an expectation spontaneously volunteered by one of the subjects ).
A more tenable explanation for the change in reactions is that the added knowledge and increased familiarity with the total situation made it possible for these subjects to be less guarded and to relax, since any reaction seemed acceptable to the examiner as `` normal ''.
We have consoled ourselves with the thought that this is a normal human reaction and is one of the consequences of any decision in an adversary proceeding.
Upon completion of the purging step, additional initiator appropriate for the molecular weight of the sample desired is added, and the system is then warmed to the polymerization temperature, at which the reaction is allowed to go to completion.

reaction and found
No detectable reaction was found at room temperature for reaction mixtures allowed to stand up to 5 hours.
Rather large differences were still found between reaction cells from different manifold fillings.
That which I found most profound and most disturbing appeared to evoke a curiously muted reaction.
Unusual thermal Diels-Alder reactivity of arenes can be found in the Wagner-Jauregg reaction.
Retrieved on 2008-02-29 </ ref > The team found that this reaction had a higher 1n cross section than the corresponding reaction with a < sup > 209 </ sup > Bi target, contrary to expectations.
As in other places, there has been a reaction and the Canadian version of the Book of Common Prayer has found supporters.
This proved to be false in 1785 by Antoine Lavoisier who found the correct explanation of the combustion as reaction with oxygen from the air.
This type of reaction is found mainly in aliphatic hydrocarbons, and rarely in aromatic hydrocarbon.
The reaction takes place in the active site, a small part of the enzyme which is usually found in a cleft or pocket lined by amino acid residues, and the rest of the enzyme is used mainly for stabilization.
It was found that the reaction of chymotrypsin with its substrate takes place in two stages, an initial “ burst ” phase at the beginning of the reaction and a steady-state phase following Michaelis-Menten kinetics.
Similarly, green deposits were found in the hair, originally thought to be a copper-based pigment used for decoration, however it was later found to be the result of a reaction between the keratin in the hair and the acid of the peat bog.
It has been shown that the antibodies found in LEMS associated with lung cancer also bind to calcium channels in the cancer cells, and it is presumed that the antibodies originally develop as a reaction to these cells.
The reaction of acid with carbonates — most commonly found as the polymorph calcite and aragonite ( CaCO < sub > 3 </ sub >) relates to the dissolution and precipitation of the mineral, which is key in the formation of limestone caves, features within them such as stalactite and stalagmites, and karst landforms.
They have found that various alcohols, aldehydes and organic acids were synthesized in reaction mixture.
Critically, reaction was mixed: a contemporary survey of reviews found 7 favourable, 3 mixed, and 5 negative.
Coeliac ( also written as celiac ) disease is a condition that is caused by an adverse immune system reaction to gliadin, a gluten protein found in wheat ( and similar proteins of the tribe Triticeae which includes other species such as barley and rye ).
After all, it is not possible to have tested every incidence of an action, and found a reaction.
There have, of course, been many, many tests, and in each one a corresponding reaction has been found.
Carbon nucleophiles are alkyl metal halides found in the Grignard reaction, Blaise reaction, Reformatsky reaction, and Barbier reaction, organolithium reagents, and anions of a terminal alkyne.

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