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In physical chemistry and chemical engineering, extent of reaction is a quantity that measures the extent to which the reaction has proceeded. Often, it refers specifically to the value of the extent of reaction when equilibrium has been reached. It is usually denoted by the Greek letter ξ.
The transition from the short-run to the long-run may be done by considering some short-run equilibrium that is also a long-run equilibrium as to supply and demand, then comparing that state against a new short-run and long-run equilibrium state from a change that disturbs equilibrium, say in the sales-tax rate, tracing out the short-run ...
In chemistry, Le Chatelier's principle (pronounced UK: / l ə ʃ æ ˈ t ɛ l j eɪ / or US: / ˈ ʃ ɑː t əl j eɪ /) [1] is a principle used to predict the effect of a change in conditions on chemical equilibrium. [2] Other names include Chatelier's principle, Braun–Le Chatelier principle, Le Chatelier–Braun principle or the equilibrium ...
In 1884, Jacobus van 't Hoff proposed the Van 't Hoff equation describing the temperature dependence of the equilibrium constant for a reversible reaction: = where ΔU is the change in internal energy, K is the equilibrium constant of the reaction, R is the universal gas constant, and T is thermodynamic temperature.
The concept of chemical equilibrium was developed in 1803, after Berthollet found that some chemical reactions are reversible. [4] For any reaction mixture to exist at equilibrium, the rates of the forward and backward (reverse) reactions must be equal. In the following chemical equation, arrows point both ways to indicate equilibrium. [5]
The equation of chemical equilibrium can be expressed symbolically as reactant(s) ⇌ product(s) The sign ⇌ means "are in equilibrium with". This definition refers to macroscopic properties. Changes do occur at the microscopic level of atoms and molecules, but to such a minute extent that they are not measurable and in a balanced way so that ...
The Hammett equation predicts the equilibrium constant or reaction rate of a reaction from a substituent constant and a reaction type constant. The Edwards equation relates the nucleophilic power to polarisability and basicity. The Marcus equation is an example of a quadratic free-energy relationship (QFER). [citation needed]
The first term in the RHS describes short-run impact of change in on , the second term explains long-run gravitation towards the equilibrium relationship between the variables, and the third term reflects random shocks that the system receives (e.g. shocks of consumer confidence that affect consumption). To see how the model works, consider two ...