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Order in the context of a chemical reaction is a concept of reaction kinetics, a subdiscipline of physical chemistry. The order of a reaction with respect to a certain reactant is defined as the power to which its concentration term in the rate equation is raised. A chemical reaction is a process involving one, two or more substances (called reactants), characterized by a chemical change and yielding one or more product(s) which are different from the reactants. ...
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Physical chemistry is the study of the physical basis of chemical systems and processes. ...
In chemistry, the reactants are the substances that exist at the start of a chemical reaction. ...
In mathematics, exponentiation is a process generalized from repeated multiplication, in much the same way that multiplication is a process generalized from repeated addition. ...
Concentration is a very common concept used in chemistry and related fields. ...
A rate equation is a mathematical expression used in chemistry to link the rate of a reaction to each reactant and their various orders. ...
- Example: For a chemical reaction A + 2B → C with a rate equation Rate = k[A]1[B]2 the reaction order with respect to A would be 1 and with respect to B would be 2.
The reaction order is not necessarily related to the stoichiometry of the reaction. The order of a reaction can be determined only by experiment (or deduced from a known reaction mechanism). It is not necessary that the order of a reaction is a whole number — zero and fractional values of order are possible. The knowledge of the empirically determined orders of a chemical reaction allows conclusions about the reaction mechanism. In chemistry, stoichiometry is the study of the combination of elements in chemical reactions. ...
From Latin ex- + -periri (akin to periculum attempt). ...
An overall description of how a reaction occurs. ...
Empirical is an adjective often used in conjunction with science, both the natural and social sciences, which means an observation or experiment based upon experience that is capable of being verified or disproved. ...
An overall description of how a reaction occurs. ...
Zeroth-order reactions are often seen for thermal chemical decompositions where the reaction rate is independent of the concentration of the reactant (changing the concentration has no effect on the speed of the reaction): chemical decomposition is the gradual fragmentation of a chemical compound into smaller molecules. ...
The reaction rate for a reactant or product in a particular reaction is defined as the amount (in moles or mass units) per unit time per unit volume that is formed or removed. ...
- A → B
- Rate = k[A]0 = k
First-order reactions with respect to all reactands are often seen for simple bi-molecular reactions where the reaction rate is directly proportional to the concentration of each reactant (doubling the concentration of one reactant speeds up the reaction by a factor of two): The word proportionality may have one of a number of meanings: In mathematics, proportionality is a mathematical relation between two quantities. ...
- A + B → C
- Rate = k[A]1[B]1 = k[A][B]
Second-order reaction with respect to B (doubling the concentration of B speeds up the reaction by a factor of four): - A + 2B → C
- Rate = k[A]1[B]2 = k[A][B]2
| Zeroth Order | First Order | Second Order | | Rate Law | ![-frac{d[a]}{dt} = k](http://en.wikipedia.org/math/cddd58154a5550a8ec13779a9ad8b311.png) | ![-frac{d[a]}{dt} = k[A]](http://en.wikipedia.org/math/66d6abdb07db6c7547bfd8496255e054.png) | ![-frac{d[a]}{dt} = k[A]^2](http://en.wikipedia.org/math/5c7873e8c961d84de4710f919919933b.png) | | Integrated Rate Law | [A] = [A]0 − kt | [A] = [A]0e( − kt) | ![frac{1}{[A]} = frac{1}{[A]_0} + kt](http://en.wikipedia.org/math/664842f28db997704b7ddbc61f6a7be8.png) | | Units of Rate Constant {k} |  |  |  | | Linear Plot | [A]vs.t | ln([A]) vs. t | ![frac{1}{[A] vs. t}](http://en.wikipedia.org/math/37b35483de4b51d146f38ddb24932774.png) | | Half-life | ![t_1/2 = frac{[A]_0}{2k}](http://en.wikipedia.org/math/721446ca46da982ba423774716afa688.png) |  | ![t_1/2 = frac{1}{[A]_0 k}](http://en.wikipedia.org/math/4fd129be4e414560bbed302efa041343.png) |
See also This article is in need of attention. ...
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