CHAP. 8: CHEMICAL EQUILIBRIUM [CONTENTS] 239
Note:In an ideal solution, the result for the standard state denoted•is the same as for
that denoted[x].
Example
Write the equilibrium constant of sulphur dioxide oxidation
0 =SO 3 (g)−
1
2
O 2 (g)−SO 2 (g)
for the standard state of a pure gaseous component in the state of an ideal gas at the temperature
of the system and the standard pressure 101.325 kPa if the reaction proceeds at a pressure of 10
kPa.
Solution
K =
aSO 3
aSO 2 a^1 O/ 22
=
(f
fst
)
SO 3
(f
fst
)
SO 2
(f
fst
) 1 / 2
O 2
=
φSO 3
φSO 2 φ^1 O/ 22
xSO 3
xSO 2 x^1 O/ 22
(
pst
p
) 1 / 2
=
φSO 3
φSO 2 φ^1 O/ 22
nSO 3
nSO 2 n^1 O/ 22
(
101. 325
∑k
i=1ni
10
) 1 / 2
,
where ni denote the amount of individual components at equilibrium, and φi their fugacity
numbers.
Example
Write the equilibrium constantsK•andK[c]for the reaction of acetic acid with 1-pentene
0 =C 7 H 14 O 2 (l)−C 5 H 10 (l)−C 2 H 4 O 2 (l).
