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  2. Rate equation - Wikipedia

    en.wikipedia.org/wiki/Rate_equation

    In chemistry, the rate equation (also known as the rate law or empirical differential rate equation) is an empirical differential mathematical expression for the reaction rate of a given reaction in terms of concentrations of chemical species and constant parameters (normally rate coefficients and partial orders of reaction) only. [1]

  3. Order of approximation - Wikipedia

    en.wikipedia.org/wiki/Order_of_approximation

    The zero of "zeroth-order" represents the fact that even the only number given, "a few", is itself loosely defined. A zeroth-order approximation of a function (that is, mathematically determining a formula to fit multiple data points) will be constant, or a flat line with no slope: a polynomial of degree 0. For example,

  4. Zero order - Wikipedia

    en.wikipedia.org/wiki/Zero_order

    Zero order reaction. Zero-order process (statistics), a sequence of random variables, each independent of the previous ones; Zero order process (chemistry), a chemical reaction in which the rate of change of concentration is independent of the concentrations; Zeroth-order approximation, an approximation of a function by a constant

  5. Reaction rate - Wikipedia

    en.wikipedia.org/wiki/Reaction_rate

    Iron rusting has a low reaction rate. This process is slow. Wood combustion has a high reaction rate. This process is fast. The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time. [1]

  6. Desorption - Wikipedia

    en.wikipedia.org/wiki/Desorption

    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 ...

  7. 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 ...

  8. 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 ...

  9. Table of thermodynamic equations - Wikipedia

    en.wikipedia.org/wiki/Table_of_thermodynamic...

    Defining equation SI unit Dimension Temperature gradient: No standard symbol K⋅m −1: ΘL −1: Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer P = / W ML 2 T −3: Thermal intensity I = / W⋅m −2