1.   The ideal gas equation can be used to calculate the relative molecular mass,, of a gas directly.

2.   So far we have not defined relative molecular mass, although we have defined relative atomic mass,.

3.   For a simple gas molecule, the relative molecular mass is simply the sum of the relative atomic masses for all the atoms in the molecule.

4.   Thus, for carbon dioxide, The relative molecular mass expressed as grams per mole is called the molar mass.

5.   Calculate the relative molecular mass of the gas.

6.   The relative molecular masses of non-volatile substances can be determined experimentally by colligative methods.