I have been asked to calculate the average separation of two water molecules based on a temperature of 22 deg C and 1 mole, with the partial pressure of the water vapour in the room being 1675 Pa.

Can anyone suggest where to start??!! I've tried using pV=nRT but what am I supposed to do with the calculated volume? I've considered using the density, mole fractions, finding the radius, looking into "mean free path" but I still don't see how any of them lead to the average separation which is usually termed r.

I would be extremely grateful for any *delete me* Thank you,

Suze