Page:Outlines of Physical Chemistry - 1899.djvu/57

 ��SECOND PAET

GASEOUS LIQUID AND SOLID STATES OF

MATTER

��I. THE GASEOUS STATE

Molecular Volume

In the gaseous state the molecular volume is a colligative property, that is to say, a property which belongs to the whole of the molecule.

One gram-molecule of any gas, measured under normal conditions of temperature and pressure (0°C. and 760 m.m.)," invariably occupies a volume of 22880 cubic centimetres.

In fact, for a gas with molecular weight m, the density with reference to hydrogen is : - - and with reference to air : y

M k,

��\ 2 x 14-435 ;

consequently the weight of one cubic centimetre is :

0*00129 m

and the volume occupied by m grams (or one gram- molecule) will be :

��= 22380 cubic centimetres.

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