Determine Specific Gravity of Glycerol Using Pycnometer

APPARATUS REQUIRED:

Pycnometer, Thermometer, Weighing balance.

CHEMICALS REQUIRED:

Water, Glycerol

THEORY:

Specific gravity is defined as the ratio of the density of a substance to the density of a given reference material.

It’s formula is ;

    Specific gravity = mass of liquid (glycerol) / mass of equivalence of water

PROCEDURE:

i) A clean and dry pycnometer (specific gravity bottle) was weighed.

ii) Then, the bottle was completely filled with water and weighed and its value was noted.

iii) After cleaning and drying, the bottle was completely filled with the liquid (glycerol) whose specific gravity was to be determined and weighed.

OBSERVATION:

Weight of empty pycnometer (w₁) = 32.80 gm

Weight of water and pycnometer (w₂) = 83.53 gm

weight of glycerol and pycnometer (w₃) = 96.69 gm

CALCULATION:

Specific gravity = mass of liquid (glycerol) / mass of equivalence of water

                        = w₃-w₁ / w₂-w₁

                        = 96.69-32.80 / 83. 53-32.80

                        = 63.89 / 50.73

                        =1.2594

RESULT:

Therefore, the specific gravity of glycerol is 1.2594 at 26°C