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For weak electrolytes (i.e. incompletely dissociated electrolytes), however, the molar conductivity strongly depends on concentration: The more dilute a solution, the greater its molar conductivity, due to increased ionic dissociation. For example, acetic acid has a higher molar conductivity in dilute aqueous acetic acid than in concentrated ...
For acids and bases the concentrations can be calculated when the value or values of the acid dissociation constant are known. For a monoprotic acid, HA, obeying the inverse square root law, with a dissociation constant K a, an explicit expression for the conductivity as a function of concentration, c, known as Ostwald's dilution law, can be ...
The term bond-dissociation energy is similar to the related notion of bond-dissociation enthalpy (or bond enthalpy), which is sometimes used interchangeably.However, some authors make the distinction that the bond-dissociation energy (D 0) refers to the enthalpy change at 0 K, while the term bond-dissociation enthalpy is used for the enthalpy change at 298 K (unambiguously denoted DH° 298).
Thermal energy in each degree of freedom of a molecule at 25 °C (kT/2) (0.01 eV) [10] 2.856×10 −21 J By Landauer's principle, the minimum amount of energy required at 25 °C to change one bit of information 3–7×10 −21 J Energy of a van der Waals interaction between atoms (0.02–0.04 eV) [11] [12] 4.1×10 −21 J
For weak acid solutions, it depends on the degree of dissociation, which may be determined by an equilibrium calculation. For concentrated solutions of acids, especially strong acids for which pH < 0, the H 0 {\displaystyle H_{0}} value is a better measure of acidity than the pH.
If different species occur in the octanol-water system by dissociation or association, several P-values and one D-value exist for the system. If, on the other hand, the substance is only present in a single species, the P and D values are identical. P is usually expressed as a common logarithm, i.e. Log P (also Log P ow or, less frequently, Log ...
The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.
Molar concentration or molarity is most commonly expressed in units of moles of solute per litre of solution. [1] For use in broader applications, it is defined as amount of substance of solute per unit volume of solution, or per unit volume available to the species, represented by lowercase : [2]