| Method |
"It is frequently useful to know the average volume of solution occupied
by each molecule, or more directly, the average distance
separating molecules in solution. This is a simple calculation based
only on the molar concentration.
In a 1-M solution, there are 6×10^23 molecules/l, = 0.6 molecules/nm^3, or inverting, the volume per molecule is V=1.66 nm^3/molecule at 1 M. For a concentration C, the volume
per molecule is V=1.66/C.
[Researchers] will take the cube root of the volume per molecule as an
indication of the average separation. d=V^(1/3)=1.18/C^(1/3), where C is in molar and d is in nanometer. Table 2 gives some typical values." |