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In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical reaction occurs. [ 1 ] A chemical mechanism is a theoretical conjecture that tries to describe in detail what takes place at each stage of an overall chemical reaction.
Under kinetic reaction control, one or both forward reactions leading to the possible products is significantly faster than the equilibration between the products. After reaction time t, the product ratio is the ratio of rate constants k and thus a function of the difference in activation energies E a or ΔG ‡:
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
Because enzymes typically increase the non-catalyzed reaction rate by factors of 10 6-10 26, and Michaelis complexes [clarification needed] often have dissociation constants in the range of 10 −3-10 −6 M, it is proposed that transition state complexes are bound with dissociation constants in the range of 10 −14 -10 −23 M. As substrate ...
In solution chemistry and biochemistry, the Gibbs free energy decrease (∂G/∂ξ, in molar units, denoted cryptically by ΔG) is commonly used as a surrogate for (−T times) the global entropy produced by spontaneous chemical reactions in situations where no work is being done; or at least no "useful" work; i.e., other than perhaps ± P dV.
Femtochemistry is the area of physical chemistry that studies chemical reactions on extremely short timescales (approximately 10 −15 seconds or one femtosecond, hence the name) in order to study the very act of atoms within molecules (reactants) rearranging themselves to form new molecules (products).
It is also an important concept in both industrial chemistry and biology. [4] Autoxidation is therefore a fairly broad term and can encompass examples of photooxygenation and catalytic oxidation . The common mechanism is a free radical chain reaction , where the addition of oxygen gives rise to hydroperoxides and their associated peroxy ...
It is also possible for the stereochemistry of the reaction to be abnormal (or unexpected) when compared with a normal reaction. While it is possible for neighbouring groups to influence many reactions in organic chemistry (e.g. the reaction of a diene such as 1,3-cyclohexadiene with maleic anhydride normally gives the endo isomer because of a ...