
9
Dilute Solutions
9.1 General considerations
Now we develop the thermodynamic treatment of dilute solutions. Quite generally
we can think of a number of substances called solutes dissolved in a liquid called the
solvent.LetN
1
,N
2
,...,N
g
be the number of moles of the solutes A
1
,A
2
,...,A
g
and
let N
0
be the number of moles of the solvent. A solution will be called Dilute when
N
i
< N
0
(9.1)
In terms of an atomist description, diluteness means the number of molecules per
unit volume of each of the solutes is much smaller than that of the solvent.
Now let u be the internal energy of a fraction of the solution containing 1 mole of
the solvent. Clearly, this fraction ...