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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. Kubo formula - Wikipedia

    en.wikipedia.org/wiki/Kubo_formula

    The Kubo formula, named for Ryogo Kubo who first presented the formula in 1957, [1] [2] is an equation which expresses the linear response of an observable quantity due to a time-dependent perturbation.

  5. Thermodynamic equations - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_equations

    The zeroth law is of importance in thermometry, because it implies the existence of temperature scales. In practice, C is a thermometer, and the zeroth law says that systems that are in thermodynamic equilibrium with each other have the same temperature. The law was actually the last of the laws to be formulated. First law of thermodynamics

  6. Zero-based numbering - Wikipedia

    en.wikipedia.org/wiki/Zero-based_numbering

    Under zero-based numbering, the initial element is sometimes termed the zeroth element, [1] rather than the first element; zeroth is a coined ordinal number corresponding to the number zero. In some cases, an object or value that does not (originally) belong to a given sequence, but which could be naturally placed before its initial element ...

  7. Thiele modulus - Wikipedia

    en.wikipedia.org/wiki/Thiele_modulus

    The Thiele modulus was developed by Ernest Thiele in his paper 'Relation between catalytic activity and size of particle' in 1939. [1] Thiele reasoned that a large enough particle has a reaction rate so rapid that diffusion forces can only carry the product away from the surface of the catalyst particle.

  8. Pre-exponential factor - Wikipedia

    en.wikipedia.org/wiki/Pre-exponential_factor

    In chemical kinetics, the pre-exponential factor or A factor is the pre-exponential constant in the Arrhenius equation (equation shown below), an empirical relationship between temperature and rate coefficient. It is usually designated by A when determined from experiment, while Z is usually left for collision frequency. The pre-exponential ...

  9. 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