Page 57 - Chemical equilibria Volume 4

The result is still complex. If we restrict ourselves to the case of perfect
solutions, then: Properties of States of Physico-Chemical Equilibrium 33
RT ⎛ ν j ⎟∑ ⎞ ℜ> [2.24]
'0
n j ⎝∑ ⎜ j ⎠
j

'0
– thus, if ∑ ν is positive, the addition of A i yields ℜ> and therefore
j
j
the equilibrium evolves from left to right of the balance equation because of
the addition of the inert component.
– if, on the other hand, ∑ ν is negative, the addition of A i leads to
j
j
ℜ<
'0 and thus the equilibrium evolves from right to left of the balance
equation because of the addition of the inert component.

2.2. Properties of all the equilibria in a system

We now consider a system in which various transformations take place
simultaneously. Let R represent the number of those transformations. Each
th
transformation is represented by a balance equation E ρ which, for the ρ
reaction, is written as:

0 = ∑ ν A k [E ρ]
k k ρ
Certain components may have a stoichiometric coefficient of 0 in
reaction ρ.

The affinity of each transformation is of the form:

A ρ =− ∑ νμ k [2.25]
k k ρ

We have seen (section 1.7) that the condition of overall equilibrium
required each transformation to have a null affinity.