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**Unformatted text preview: **hat their purpose is to make sure that the free
energy calculated for nonideal solutions yield the correct result without changing
the general form of the equation. Activities are denoted by the letter a, and is
commonly expressed in terms of activity coefficients γ which, when multiplied by
the molality of the species, yields the activity, i.e., a = γm.
K
a ? nR ? nS m nR m nS
a nR a nS
RS
RS
R
S
= nP nQ = nP nQ % nP nQ .
aP aQ
?P ?Q
mP mQ It is generally understood that in these equations, the units of the concentrations or
activities are cancelled by a term-by-term division of the standard concentration.
In order to keep the notation simple, we refrain from explicitl...

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