Consider an ideal gas at 27 degree C and 1 atm. To get some idea how close these molecules are to each other, on the average, imagine them to be uniformle spaced, with each molecules at the center of a samll cube.
(a) What is the length of an edge of each cube if adgacent cubes touch but not overlap?
(b) How does this distance compare with the diameter of typical molucule?
(c) How does their separation compare with the spacing of atoms in solids, which typically about 0.3nm apart?