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1、INTERNATIONAL STANDARD 758 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION .MEXflYHAPOflHAI OPrAHM3AUMR n0 CTAHllAPTUJAllUU .ORGANISATION INTERNATIONALE DE NDRMALlSATlON Liquid chemical products for industrial use - Determination of density at 2Q “C Prod these documents are in the process of being tr
2、ansformed into International Standards. As part of this process, Technical Committee ISO/TC 47, Chemistry, has reviewed IS0 Recommendation R 758-1968 and found it technically suitable for transformation. International Standard IS0 758 therefore replaces IS0 Recommendation R 758-1968, to which it is
3、technically identical. IS0 Recommendation R 758 has been approved by the member bodies of the following countries : Australia Germany Austria Hungary Belgium India Chile Israel Colombia Italy Czechoslovakia Japan Egypt, Arab Rep. of Korea, Rep. of France Netherlands Poland Portugal Romania Spain Uni
4、ted Kingdom U.S.S.R. Yugoslavia The member body of the following country had expressed disapproval of the Recommendation on technical grounds : U.S.A. The member body of the following country disapproved the transformation of the Recommendation into an International Standard : Netherlands 0 Internat
5、ional Organization for Standardization, 1976 0 Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 22:12:29 MDTNo reproduction or networking permitted without
6、license from IHS -,-,- INTERNATIONAL STANDARD IS0 758-1976 (E) Liquid chemical products for industrial use - Determination of density at 20 “C 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies a reference method for the determination of the density, at 20 “C, of liquid chemical
7、products for industrial use. 2 REFERENCE IS0 3507, Pyknometers. 3 DEFINITION density at 20 C of a material : The mass of unit volume of the material at 20 “C. It is expressed in grams per millilitre. 4 PRINCIPLE Determination of the mass at 20 “C of a volume of the material contained in a pyknometer
8、 flask, and determination of the volume of the latter by determining the mass of a corresponding volume of water at 20 C Calculation of the density by dividing the mass of the material by the capacity of the flask. 5 APPARATUS Ordinary laboratory apparatus, and 5.1 Pyknometer flask, type 3 (Gay-Luss
9、ac) (see ISO3507). made of glass and of a size and type suitable for use with the material under test, preferably 25 or 50 ml (see the figure). 5.2 Water bath, capable of being controlled at 20 f 0.1 C. 6 PROCEDURE 6.1 Clean and dry the flask (5.1) and weigh it, with its stopper, to the nearest 0,00
10、1 g. Fill the flask with freshly boiled and cooled distilled water, and determine the apparent mass of the contents, previously brought to 20 f 0,l C in the water bath (5.2). 6.2 Empty, clean and dry the flask, fill it with the sample under test, and determine in a similar manner the apparent mass o
11、f sample contained in the flask at 20 C. NOTE - With volatile liquids, it is essential that suitable precautions be taken to avoid loss by evaporation. 7 EXPRESSION OF RESULTS The density of the sample at 20 C, in grams per millilitre, is given by the formula where ml +A -XX m2 +A ml is the apparent
12、 mass, in grams, of sample required to fill the flask at 20 C; m2 is the apparent mass, in grams, of water required to fill the flask at 20 C; p is the density of water at 20 C = 0,998 2 g/ml; A is the buoyancy correction = pa xm2, where pa is the density of air = 0,001 2 g/ml.* Calculate the result
13、 to three decimal places. 8 TEST REPORT The test report shall include the following particulars : a) the reference of the method used; b) the results and the method of expression used; c) anv unusual features noted during the determination; d) any operation not included in this International Standar
14、d or in the International Standard to which reference is made, or regarded as optional. -_ x This figure varies slightly with atmopheric conditions, but normal variations will have a negligible effect on density determinations. 1 Copyright International Organization for Standardization Provided by I
15、HS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 22:12:29 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 758-1976 (E) 49,723 cm3 at 20 C FIGURE - 50 ml pyknometer flask,type 3 (Gay-Lussac) 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 22:12:29 MDTNo reproduction or networking permitted without license from IHS -,-,-
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