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The equilibrium constant of a chemical reaction is the value of its reaction quotient at chemical equilibrium, a state approached by a dynamic chemical system after sufficient time has elapsed at which its composition has no measurable tendency towards further change. For a given set of reaction conditions, the equilibrium constant is ...
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.
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.
These calculations find application in many different areas of chemistry, biology, medicine, and geology. For example, many compounds used for medication are weak acids or bases, and a knowledge of the p K a values, together with the octanol-water partition coefficient , can be used for estimating the extent to which the compound enters the ...
It is used in chemistry to keep track of the changes in amount of substance of the reactants and also organize a set of conditions that one wants to solve with. [1] Some sources refer to a RICE table (or box or chart) where the added R stands for the reaction to which the table refers. [ 2 ]
When pure substances (liquids or solids) are involved in equilibria their activities do not appear in the equilibrium constant [14] because their numerical values are considered one. Applying the general formula for an equilibrium constant to the specific case of a dilute solution of acetic acid in water one obtains
If a substance is present as several chemical species in the partition system due to association or dissociation, each species is assigned its own K ow value. A related value, D, does not distinguish between different species, only indicating the concentration ratio of the substance between the two phases. [citation needed]
Even at pH 7–7.2, the range of biological pH values, the aqueous phase may support an equilibrium between more than one protonated form. log p is determined from the analytical concentration of the substance in the aqueous phase, that is, the sum of the concentration of the different species in equilibrium.