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. Euler method - Wikipedia

    en.wikipedia.org/wiki/Euler_method

    For this reason, the Euler method is said to be a first-order method, while the midpoint method is second order. We can extrapolate from the above table that the step size needed to get an answer that is correct to three decimal places is approximately 0.00001, meaning that we need 400,000 steps.

  4. 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 ...

  5. 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.

  6. Numerical methods for ordinary differential equations - Wikipedia

    en.wikipedia.org/wiki/Numerical_methods_for...

    For example, the second-order equation y′′ = −y can be rewritten as two first-order equations: y′ = z and z′ = −y. In this section, we describe numerical methods for IVPs, and remark that boundary value problems (BVPs) require a different set of tools. In a BVP, one defines values, or components of the solution y at more than one ...

  7. Runge–Kutta methods - Wikipedia

    en.wikipedia.org/wiki/Runge–Kutta_methods

    Runge–Kutta–Nyström methods are specialized Runge–Kutta methods that are optimized for second-order differential equations. [22] [23] A general Runge–Kutta–Nyström method for a second order ODE system ¨ = (,,,) with order is with the form

  8. SN2 reaction - Wikipedia

    en.wikipedia.org/wiki/SN2_reaction

    The rate of an S N 2 reaction is second order, as the rate-determining step depends on the nucleophile concentration, [Nu −] as well as the concentration of substrate, [RX]. [1] r = k[RX][Nu −] This is a key difference between the S N 1 and S N 2 mechanisms.

  9. SN1 reaction - Wikipedia

    en.wikipedia.org/wiki/SN1_reaction

    the simple first-order rate law described in introductory textbooks. Under these conditions, the concentration of the nucleophile does not affect the rate of the reaction, and changing the nucleophile (e.g. from H 2 O to MeOH) does not affect the reaction rate, though the product is, of course, different. In this regime, the first step ...