enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Rate equation - Wikipedia

    en.wikipedia.org/wiki/Rate_equation

    If the concentration of a reactant remains constant (because it is a catalyst, or because it is in great excess with respect to the other reactants), its concentration can be included in the rate constant, leading to a pseudo–first-order (or occasionally pseudo–second-order) rate equation. For a typical second-order reaction with rate ...

  3. Rate-determining step - Wikipedia

    en.wikipedia.org/wiki/Rate-determining_step

    In fact, however, the observed reaction rate is second-order in NO 2 and zero-order in CO, [5] with rate equation r = k[NO 2] 2. This suggests that the rate is determined by a step in which two NO 2 molecules react, with the CO molecule entering at another, faster, step. A possible mechanism in two elementary steps that explains the rate ...

  4. Order of accuracy - Wikipedia

    en.wikipedia.org/wiki/Order_of_accuracy

    Consider , the exact solution to a differential equation in an appropriate normed space (, | | | |). Consider a numerical approximation u h {\displaystyle u_{h}} , where h {\displaystyle h} is a parameter characterizing the approximation, such as the step size in a finite difference scheme or the diameter of the cells in a finite element method .

  5. Reaction rate constant - Wikipedia

    en.wikipedia.org/wiki/Reaction_rate_constant

    where A and B are reactants C is a product a, b, and c are stoichiometric coefficients,. the reaction rate is often found to have the form: = [] [] Here ⁠ ⁠ is the reaction rate constant that depends on temperature, and [A] and [B] are the molar concentrations of substances A and B in moles per unit volume of solution, assuming the reaction is taking place throughout the volume of the ...

  6. Molecularity - Wikipedia

    en.wikipedia.org/wiki/Molecularity

    The kinetic order of any elementary reaction or reaction step is equal to its molecularity, and the rate equation of an elementary reaction can therefore be determined by inspection, from the molecularity. [1] The kinetic order of a complex (multistep) reaction, however, is not necessarily equal to the number of molecules involved.

  7. Reactions on surfaces - Wikipedia

    en.wikipedia.org/wiki/Reactions_on_surfaces

    The rate equation is complex, and the reaction order is not clear. In experimental work, usually two extreme cases are looked for in order to prove the mechanism. In them, the rate-determining step can be: Limiting step: adsorption/desorption

  8. Order of approximation - Wikipedia

    en.wikipedia.org/wiki/Order_of_approximation

    First-order approximation is the term scientists use for a slightly better answer. [3] Some simplifying assumptions are made, and when a number is needed, an answer with only one significant figure is often given ("the town has 4 × 10 3, or four thousand, residents"). In the case of a first-order approximation, at least one number given is exact.

  9. Heun's method - Wikipedia

    en.wikipedia.org/wiki/Heun's_method

    Assuming that the quantity (,) on the right hand side of the equation can be thought of as the slope of the solution sought at any point (,), this can be combined with the Euler estimate of the next point to give the slope of the tangent line at the right end-point. Next the average of both slopes is used to find the corrected coordinates of ...