A sealed cylinder contains a substance of mass $m$. In its liquid state, the substance has a density of 1024 kg m^-3. When heated, it vaporises completely to a gas of density 2.00 kg m^-3.

Assuming a simplified model where each molecule occupies a cube of side length equal to the average molecular separation, what is the ratio of the average molecular separation in the gas phase to that in the liquid phase?