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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 distribution coefficient, log D, is the ratio of the sum of the concentrations of all forms of the compound (ionized plus un-ionized) in each of the two phases, one essentially always aqueous; as such, it depends on the pH of the aqueous phase, and log D = log P for non-ionizable compounds at any pH.
Fugacity and BCF relate to each other in the following equation: = [6] where Z Fish is equal to the Fugacity capacity of a chemical in the fish, P Fish is equal to the density of the fish (mass/length 3), BCF is the partition coefficient between the fish and the water (length 3 /mass) and H is equal to the Henry's law constant (Length 2 /Time 2) [6]
The octanol-water partition coefficient, usually expressed as its logarithm (Log P), is a measure of differential solubility of a compound in a hydrophobic solvent and a hydrophilic solvent (water). The logarithm of these two values enables compounds to be ranked in terms of hydrophilicity (or hydrophobicity).
Taking k such that φ + 2k π is within the defined interval for the principal arguments, then a k is called the principal value of the logarithm, denoted Log(z), again with a capital L. The principal argument of any positive real number x is 0; hence Log(x) is a real number and equals the real
Hydrolysis constants are usually reported in the β * form and therefore often have values much less than 1. For example, if log K = 4 and log K W = −14, log β * = 4 + (−14) = −10 so that β * = 10 −10. In general when the hydrolysis product contains n hydroxide groups log β * = log K + n log K W
In a complex plane, > is identified with the positive real axis, and is usually drawn as a horizontal ray. This ray is used as reference in the polar form of a complex number . The real positive axis corresponds to complex numbers z = | z | e i φ , {\displaystyle z=|z|\mathrm {e} ^{\mathrm {i} \varphi },} with argument φ = 0. {\displaystyle ...
A random variable which is log-normally distributed takes only positive real values. It is a convenient and useful model for measurements in exact and engineering sciences, as well as medicine, economics and other topics (e.g., energies, concentrations, lengths, prices of financial instruments, and other metrics).