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pH is defined in terms of the activity of the hydrogen ion pH = −log 10 {H +} In the approximation of ideal behaviour, activity is replaced by concentration. pH is measured by means of a glass electrode, a mixed equilibrium constant, also known as a Brønsted constant, may result.
log 10 β values between about 2 and 11 can be measured directly by potentiometric titration using a glass electrode. This enormous range of stability constant values (ca. 100 to 10 11) is possible because of the logarithmic response of the electrode. The limitations arise because the Nernst equation breaks down at very low or very high pH.
For a reversible reaction, the equilibrium constant can be measured at a variety of temperatures. This data can be plotted on a graph with ln K eq on the y-axis and 1 / T on the x axis. The data should have a linear relationship, the equation for which can be found by fitting the data using the linear form of the Van 't Hoff equation
In chemical thermodynamics, the reaction quotient (Q r or just Q) [1] is a dimensionless quantity that provides a measurement of the relative amounts of products and reactants present in a reaction mixture for a reaction with well-defined overall stoichiometry at a particular point in time.
However, the extent of reaction can be used to describe the changes on a common footing as needed. The change of the number of moles of A can be represented by the equation d n A = − d ξ {\displaystyle dn_{A}=-d\xi } , the change of B is d n B = + 2 d ξ {\displaystyle dn_{B}=+2d\xi } , and the change of C is d n C = + 3 d ξ {\displaystyle ...
The binding constant, or affinity constant/association constant, is a special case of the equilibrium constant K, [1] and is the inverse of the dissociation constant. [2] It is associated with the binding and unbinding reaction of receptor (R) and ligand (L) molecules, which is formalized as:
As the value of ρ is related to the charge during the rate determining step, mechanisms can be devised based on this information. If the mechanism for the reaction of an aromatic compound is thought to occur through one of two mechanisms, the compound can be modified with substituents with different σ values and kinetic measurements taken.
In chemistry, biochemistry, and pharmacology, a dissociation constant (K D) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions.