Two different small‐angle X‐ray scattering methods have been used to determine the electron density of the particles in a colloidal silica suspension. In the first method, the electron density of the particles was calculated from the measured change of the zero‐angle scattered intensity caused by the addition of known quantities of sucrose to increase the solvent electron density. In the second method, the scattering from the suspension was compared with the scattering from a nearly ideal gas. Within an experimental uncertainty of about 5%, the electron density of the silica particles was found by both methods to have a value corresponding to pure SiO2 particles with the mass density 2.28 g.cm−3 which is listed in the manufacturer's literature describing the suspensions. This determination of the electron density will enable these suspensions to be used as standard samples in determinations of the ratio of the scattered intensity to the incident intensity.
The total solid paraffins (boiling 170"C+) separated from Mukta crude by urea adduction and its narrow fractions were analysed for their structural composition by proton NMR, infrared spectroscopy and gas chromatography. It has been observed that CH 21CHJ ratio in these samples varies from 7.9 to 13.8 while their average carbon number ranges from 17 to 29.6. The CH 21CHJ ratio and chain length of paraffins increases with increase in boiling range of the fractions.
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