á841ñSPECIFIC GRAVITY
Unless otherwise stated in the individual monograph,the specific gravity determination is applicable only to liquids,and,unless otherwise stated,is based on the ratio of the weight of a substance in air at 25
to that of an equal volume of water at the same temperature.Where a temperature is specified in the individual monograph,the specific gravity is the ratio of the weight of the substance in air at the specified temperature to that of an equal volume of water at the same temperature.When the substance is a solid at 25,determine the specific gravity at the temperature directed in the individual monograph,and refer to water at 25.
to that of an equal volume of water at the same temperature.Where a temperature is specified in the individual monograph,the specific gravity is the ratio of the weight of the substance in air at the specified temperature to that of an equal volume of water at the same temperature.When the substance is a solid at 25,determine the specific gravity at the temperature directed in the individual monograph,and refer to water at 25.Procedure— Select a scrupulously clean,dry pycnometer that previously has been calibrated by determining its weight and the weight of recently boiled water contained in it at 25
.Adjust the temperature of the substance to about 20,and fill the pycnometer with it.Adjust the temperature of the filled pycnometer to 25,remove any excess of the substance,and weigh.Subtract the tare weight of the pycnometer from the filled weight of the pycnometer.
The specific gravity of the substance is the quotient obtained by dividing the weight of the substance contained in the pycnometer by the weight of water contained,both determined at 25unless otherwise directed in the individual monograph.
unless otherwise directed in the individual monograph.