The Mechanism of Chromatographic Retention - The Association of Methanol with Water > Page 33
where (MW), (MM) and (MMW) are the molecular weights of water, methanol and the methanol/water associate respectively.
In a similar manner the total weight (mi) of the mixture originally containing a volume fraction (ai) of methanol and a volume fraction (1-ai) of water will be
mi = wW + wM + wMW
and the density (di) of the mixture will be (17)
The additive and constitutive properties of the molar refraction of a substance has been known for nearly a century and the molar refraction is defined by the following equation,