Determination of weight per Milliliter (Wt. per ml).

Weight per Millilitre
( Wt. per ml)

The weight per millilitre of a liquid is
the weight, in gm, of 1 ml of a liquid when weighed in air at 25⁰, unless
otherwise specified.

Method

Select a thoroughly clean and
dry Pycnometer. 

Calibrate the Pycnometer by filling it with recently boiled and cooled water at
25⁰ and weighing the contents. 

Assuming that the weight of 1 ml of water at 25⁰
when weighed in air of density 0.0012 gm per ml is 0.99602 gm, calculate the capacity
of the Pycnometer. 

Adjust the temperature of the substance being examined, to about 20⁰
and fill the Pycnometer with it. 

Adjust the temperature of the substance being
examined, to about 20⁰ and fill the Pycnometer with it. 

Adjust the temperature of the filled
Pycnometer to 25⁰, remove any excess of the substance and weigh. 

Subtract th tare
weight of the Pycnometer from the filled weight of the Pycnometer. 

Determine
the weight per millilitre by dividing the weight in air, in gm, of the quantity of liquid which fills
the Pycnometer at the specified temperature, by the capacity expressed in ml, of the
Pycnometer at the same temperature.