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Transition state structures can be determined by searching for first-order saddle points on the potential energy surface (PES) of the chemical species of interest. [4] A first-order saddle point is a critical point of index one, that is, a position on the PES corresponding to a minimum in all directions except one.
First-order phase transitions exhibit a discontinuity in the first derivative of the free energy with respect to some thermodynamic variable. [6] The various solid/liquid/gas transitions are classified as first-order transitions because they involve a discontinuous change in density, which is the (inverse of the) first derivative of the free ...
Using the Eyring equation, there is a straightforward relationship between ΔG ‡, first-order rate constants, and reaction half-life at a given temperature. At 298 K, a reaction with Δ G ‡ = 23 kcal/mol has a rate constant of k ≈ 8.4 × 10 −5 s −1 and a half life of t 1/2 ≈ 2.3 hours, figures that are often rounded to k ~ 10 −4 s ...
In thermodynamics, nucleation is the first step in the formation of either a new thermodynamic phase or structure via self-assembly or self-organization within a substance or mixture. Nucleation is typically defined to be the process that determines how long an observer has to wait before the new phase or self-organized structure appears.
First-order logic, a formal logical system used in mathematics, philosophy, linguistics, and computer science; First-order predicate, a predicate that takes only individual(s) constants or variables as argument(s) First-order predicate calculus; First-order theorem provers; First-order theory; Monadic first-order logic
This data can be plotted on a graph with ln K eq on the y-axis and 1 / T on the x axis. The data should have a linear relationship, the equation for which can be found by fitting the data using the linear form of the Van 't Hoff equation
[A] can provide intuitive insight about the order of each of the reagents. If plots of v / [A] vs. [B] overlay for multiple experiments with different-excess, the data are consistent with a first-order dependence on [A]. The same could be said for a plot of v / [B] vs. [A]; overlay is consistent with a first-order dependence on [B].
For first order desorption, the activation energy is estimated from the temperature (T p) at which the desorption rate is a maximum. Using the equation for rate of desorption (Polyani Winer equation), one can find T p , and Redhead shows that the relationship between T p and E can be approximated to be linear, given that the ratio of the rate ...