chemical kinetics, the entropy of activation of a reaction is one of the two parameters (along with the enthalpy of activation) that are typically obtained...

enthalpy of activation (ΔH‡, also written Δ‡Hɵ), the standard entropy of activation (ΔS‡ or Δ‡Sɵ), and the standard Gibbs energy of activation (ΔG‡ or...

specifically, we can write the Gibbs free energy of activation in terms of enthalpy and entropy of activation: ΔG‡ = ΔH‡ − T ΔS‡. Then, for a unimolecular...

of activation and S‡ i are the entropies of activation. Between the enthalpy and entropy changes of a series of similar reactions (enthalpy–entropy compensation)...

theory, also known as activated-complex theory. If one assumes a constant enthalpy of activation and constant entropy of activation, the Eyring equation...

of activation, Δ S ‡ {\displaystyle \Delta S^{\ddagger }} is the entropy of activation, Δ H ‡ {\displaystyle \Delta H^{\ddagger }} is the enthalpy of...

Values of A for some reactions can be found at Collision theory. According to transition state theory, A can be expressed in terms of the entropy of activation...

orientation, and the entropy of activation. The expression exp ⁡ ( − E a / R T ) {\displaystyle \exp(-E_{\text{a}}/RT)} represents the fraction of the molecules...

of f-electrons. The reaction is thought to proceed via cycloaddition. Indeed, the rate of the reaction is characterized by a highly negative entropy of...

enthalpy of activation ΔH‡ and the entropy of activation ΔS‡, based on the defining formula ΔG‡ = ΔH‡ − TΔS‡. In effect, the free energy of activation takes...

molecular geometry. The entropy of activation is characteristically positive for these reactions, which indicates that the disorder of the reacting system...

molecular geometry. The entropy of activation is characteristically positive for these reactions, which indicates that the disorder of the reacting system...

racemization is in the range 35 - 42 kcal/mol and the corresponding entropy of activation is -8 - +4 cal/mol-K. The barriers are lower for allylic and benzylic...

negative entropy of activation similar to that of the Diels-Alder reaction, suggesting that the transition state is highly ordered, which is a signature of concerted...

High-entropy alloys (HEAs) are alloys that are formed by mixing equal or relatively large proportions of (usually) five or more elements. Prior to the...

the entropy of activation is negative, which indicates an increase in order in the system. These reactions follow second order kinetics: the rate of the...

This reaction generally proceeds with a low activation energy and a large negative entropy of activation. This further supports the cyclic three member...

about 1 μs and 1 s. The enthalpy and entropy of activation, ΔH‡ and ΔS‡ can be obtained by observing the variation of rate constant with temperature. Note...

rearrangement to amino ketones. Hammett analysis and a very negative entropy of activation suggest that the reaction proceeds in a single step through a concerted...

energy of the system H {\textstyle H} is the enthalpy of the system S {\textstyle S} is the entropy of the system T {\textstyle T} is the temperature of the...

and time delay estimation it is useful to estimate the differential entropy of a system or process, given some observations. The simplest and most common...

were measured for seven of the dienes permitting calculations of the enthalpy of activation (ΔH‡) and entropy of activation (ΔS‡) for these reactions...

breaking of the N-H bond more difficult. The exceptionally high negative entropy of activation values observed can be explained by the high degree of organization...

pre-exponential factors AD/AH is not equal to 1. A large negative entropy of activation. The geometries of the reactants and products are usually very similar. Also...

has near-zero entropy of activation, while typical Claisen rearrangements in solution have very negative entropies of activation. The use of cation-pi interactions...

lowering of the activation barrier until 61,5 kJ/mol (M06-2X/def2-TZVPP), if S replaces O on the enophile. By computationally examining both the activation barriers...

Such associative reactions are characterized by large negative entropies of activation, in this case: -178 and -143 kJ/(mol·K) for Pd and Pt, respectively...

spontaneously if the entropy change of the surroundings is both positive in sign and has a larger magnitude than the entropy change of the system: Δ S surroundings...

and the substrate restrict conformational degrees of freedom, such that the entropy of activation is effectively reduced to zero, and thereby promotes...

University of Alberta suggested that the humor of certain nonsense words can be explained by whether they seem rude, and by the property of entropy: the improbability...