# Determination of specific gravity of liquid sample by using Pycnometer

Title: Standard operating procedure for determination of specific gravity of liquid sample by using Pycnometer.

1.0                                               OBJECTIVE:

To lay down a procedure for determination of specific gravity of liquid sample by using Pycnometer.

2.0                                               SCOPE:

This SOP shall be applicable to Q.C Dept.

3.0                                               RESPONSIBILITY:

3.1                                Doing: Q.C Analyst.

3.2                                Checking: Q.C-Manager.

4.0                                               ACCOUNTABILITY:

4.1                                Head of the Q.C Department.

5.0                                               MATERIAL AND EQUIPMENT:

5.1                                Pycnometer.

5.2                                Sample.

5.3                                Purified water.

6.0                                               PROCEDURE:

6.1                                Make sure that the instrument is clean.

6.2                                Operate the apparatus according to SOP.

6.3                                Ensure the solid to be tested must be weigh carefully.

6.4                                Ensure that the liquid to be tested has been thoroughly, but gently stirred and that any entrained air has been removed.

6.5    Weigh the empty Pycnometer with stoppered on the analytical weighing balance i.e. W1.

6.6    Fill the exact volume of your liquid sample solution into the Pycnometer carefully. It should come nearly to the rim of the Pycnometer.

6.7    Insert the stopper and tapping the sides gently to remove the air bubble.

6.8    Firmly and evenly seat the stopper on the Pycnometer flask. A small amount of liquid should appear from the hole in the stopper.

6.9    Dry the sides and weigh the filled Pycnometer with stoppered again on the analytical weighing balance i.e. W2.

6.10                            Record the observations into the annexure-2.

6.11                            Note down the temperature of the sample.

6.12                            Calculate the sample weight by using formula:

Sample weight (g) = (wt. of filled Pycnometer with stopper) – (wt. of empty Pycnometer with stopper)

6.13                            Calculate the specific gravity of the liquid sample by using formula:

Specific gravity of sample = ___Density of the substance___

Density of the purified water

Or

Specific gravity of sample = ________Weight of the substance_______

Weight of an equal volume of water

6.14                            Precautions:

6.14.1       Be certain to use the known density value at the correct temperature.

6.14.2       Do the same for the procedure in the liquid unknown. Calculate the density of the unknowns.

7.0                                               REVISION LOG:

 Revision No. Effective Date Reason 00 New SOP

8.0                                               REFERENCES:

8.1                                Not Applicable.

9.0                                               ANNEXURES:

Annexure 1: Specific gravity of water at different temperatures.

Annexure 2: Observations and calculations of specific gravity by using Pycnometer.

Annexure: 1

Specific gravity of water at different temperature

 Specific gravity of purified water (g/cm3) At temperature (oC) 0.9957 30oC 0.99602 25oC 0.9982 20oC 0.9997 10oC 1.0000 4oC 0.9998 0oC

Annexure: 2

Observations and calculations of specific gravity by using Pycnometer

OBSERVATIONS AND CALCULATIONS OF SPECIFIC GRAVITY BY USING PYCNOMETER

 Apparatus: Room: Date:

 Temperature (oC): Density of the sample (g/cm3): Density of the purified water (g/cm3): Weight of the sample to tested (g): Sample solution:

Weigh the empty Pycnometer with stopper = W1 = _____________g.

Weigh the filled Pycnometer with stopper = W2 = ______________g.

Sample weight (g) = (wt. of filled Pycnometer with stopper) – (wt. of empty Pycnometer with stopper)

Specific gravity of the liquid sample by using formula:

Specific gravity of sample = ___Density of the substance___

Density of the purified water

Or

Specific gravity of sample = ______Weight of the substance_______

Weight of an equal volume of water

 Results:

Remarks: _______________________________________________________________

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