Fugacity: It is derived from Latin, expressed as fleetness or escaping ...

EFFECT OF TEMPERATURE ON EQUILIBRIUM CONSTANT K
Gibb’s - Helmoholtz equation at constant pressure is given
o G
d
T H
o
but G RT
ln K
2
dT T
RT
ln K
d
T
H d R ln K
H
or
2 2
dT T dT T
d ln K
H
Van't Hoff equation.
2
dT RT
This may be integrated to find the effect of temperature on K
K2
T2
When H
is contant d lnK
K1
T1
K2 ln
K1
H
1 1
R T2 T1
if K is known at T ,then
K can be calculated at other T
1 1
ln K
H
dT 2
RT
2 2
When H varies with T
d
dT
0
H
2
RT
T
I
d ln K
dT 2
RT 2R 3R
RT
0
ln T
ln K =
R 2R 6R
RT
G RT ln K
2
T T I
M
Where M is a consatnt of integration
2
0 ln T T T
I
G RT M
R 2R 6R
RT
T T
G T I MRT
2 6
2 3
0
ln T