User guide

Where ‘H’ is the enthalpy of the gas, calculated as: H = U + pV.
MOLECULAR_NETWORKS_LOGP
The partition coefficient is a ratio of concentrations of un-ionized compound between two solutions. To measure the
partition coefficient of ionizable solutes, the pH of the aqueous phase is adjusted so that the predominant form of the
compound is un-ionized. The logarithm of the ratio of the concentrations of the un-ionized solute in the solvents is
called LogP.
Normally, one of the solvents chosen is water; the second is hydrophobic, such as octanol.
MOLECULAR_NETWORKS_LOGS
MOLECULAR_NETWORKS_LogS determines the solubility of a substance, measured in mol/liter. The aqueous sol-
ubility of a compound is known to significantly affect absorption and distribution characteristics of that compound.
MOLECULAR_NETWORKS_PKa
MOLECULAR_NETWORKS_PKa is the negative log of the acid dissociation constant Ka. It describes the tendency
of compounds or ions to dissociate in solution.
Mass
This is the mass of one molecule of a substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of
one atom of 12C). Also called molecular mass.
Melting point
Is the temperature at which a solid becomes a liquid at standard atmospheric pressure. At the melting point, the solid
and liquid phase exist in equilibrium. The formula to calculate melting point is:
Where ‘T’ is the temperature at the melting point, ‘DS’ is the change in entropy of melting, and ‘DH’ is the change in
enthalpy of melting.
Molar refractivity
Is a measure of the total polarizability of one mole of a substance. It is dependent on the temperature, index of refrac-
tion, and pressure.
The molar refractivity, ‘A’ is expressed as:
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