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The degree of dissociation in gases is denoted by the symbol α, where α refers to the percentage of gas molecules which dissociate. Various relationships between K p and α exist depending on the stoichiometry of the equation. The example of dinitrogen tetroxide (N 2 O 4) dissociating to nitrogen dioxide (NO 2) will be taken.
The equation for mass-balance in hydrogen ions can then be written as T H = [H +] + [A −][H +]/K a − K w / [H +] Titration curves for addition of a strong base to a weak acid with pK a of 4.85. The curves are labelled with the concentration of the acid. where K w represents the self-dissociation constant of water.
The dissociation involves cleaving of the molecular bonds in the adsorbate, and formation of new bonds with the substrate. Breaking the atomic bonds of the dissociating molecule requires a large amount of energy, thus dissociative adsorption is an example of chemisorption , where strong adsorbate-substrate bonds are created. [ 1 ]
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.
With specific values for C a and K a this quadratic equation can be solved for x. Assuming [4] that pH = −log 10 [H +] the pH can be calculated as pH = −log 10 x. If the degree of dissociation is quite small, C a ≫ x and the expression simplifies to = and pH = 1 / 2 (pK a − log C a).
The dissociation rate constant is defined using K off. [2] The Michaelis-Menten constant is denoted by K m and is represented by the equation K m = (K off + K cat)/ K on [definition needed]. The rates that the enzyme binds and dissociates from the substrate are represented by K on and K off respectively.
Other structural factors that influence the magnitude of the acid dissociation constant include inductive effects, mesomeric effects, and hydrogen bonding. Hammett type equations have frequently been applied to the estimation of pK a. [3] [4] The quantitative behaviour of acids and bases in solution can be understood only if their pK a values ...
b c is the colligative molality, calculated by taking dissociation into account since the boiling point elevation is a colligative property, dependent on the number of particles in solution. This is most easily done by using the van 't Hoff factor i as b c = b solute · i , where b solute is the molality of the solution. [ 3 ]