GB/T 611-2021 English PDF (GBT611-2021)

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GB/T 611-2021: Chemical reagent -- General method for the determination of density
GB/T 611-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.040.30
CCS G 60
Replacing GB/T 611-2006
Chemical reagent - General method for the
determination of density
(ISO 6353-1:1982, Reagents for chemical analysis –
Part 1: General test methods, NEQ)
ISSUED ON: AUGUST 20, 2021
IMPLEMENTED ON: MARCH 1, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Test method ... 5
Chemical reagent - General method for the
determination of density
1 Scope
This document specifies the general methods for determining the density of
liquid chemical reagents by the density bottle method, Westphal balance
method, and the oscillation-type liquid density meters method.
This document applies to the determination of the density of liquid chemical
reagents.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) is applicable to this standard.
GB/T 6682 Water for analytical laboratory use -- Specification and test
methods
JJG 130 Verification Regulation of Liquid-in-Glass Thermometers for
Working
JJG 171 Verification Regulation of Relative Density Balance for Liquid
JJG 1058 Verification regulation of laboratory oscillation-type liquid density
meters
3 Terms and definitions
The following terms and definitions apply to this document.
3.1 Density
The mass of a substance per unit volume at 20 °C.
4.2.3.1 Wash and dry the density bottle; weigh the bottle, a thermometer (or
bottle stopper), and a side escutcheon together; then remove the thermometer
(or bottle stopper) and the side escutcheon. Fully-fill the density bottle with the
water that has been freshly boiled and then cooled to about 15 °C; there shall
be no air bubbles; insert a thermometer (or bottle stopper); place the density
bottle into a constant-temperature water bath of 20.0 °C ± 0.1 °C, until the liquid
temperature in the density flask reaches 20 °C, and the liquid level in the side
tube is flush with the mouth of the side tube; cover the side escutcheon at once.
Take out the density bottle; wipe the water from the bottle's outer wall with filter
paper; weigh it immediately.
4.2.3.2 Repeat the operation of 4.2.3.1 with the sample.
4.2.4 Result calculation
The density ρ of the sample is, expressed in "g/mL", calculated according to
formula (1):
The air buoyancy correction value A, expressed as "g", is calculated according
to formula (2):
4.3.3 Determination
4.3.3.1 Hang the plumb on the end of the balance beam with a thin platinum
wire, and adjust the screws on the base to make the beam and the tip of the
pointer align with each other.
4.3.3.2 Let the plumb be immersed in a glass cylinder containing the water that
has been boiled and then cooled to about 20 °C. There shall be no air bubbles.
The glass cylinder shall be placed in a constant-temperature water bath with
the temperature at 20.0 °C ± 0.1 °C. Adjust the weight to let the beam and the
pointer realign with each other; record the reading.
4.3.3.3 Take out the plumb and make it completely dry. At the same temperature,
replace the water with the sample and repeat the operation in 4.3.3.2.
4.3.4 Result calculation
The density ρ of the sample is, expressed in "g/mL", calculated according to
formula (3):
Where:
m2 --- the reading of the weight when the plumb is immersed in the sample;
m1 --- the reading of the weight when the plumb is immersed in water;
ρ0 --- the density of water at 20 °C, 0.99820 g/mL.
4.4 Oscillation-type liquid density meters method
4.4.1 Principle of the method
After a U-shaped glass oscillating tube is filled with a certain volume of liquid,