Physical Chemistry 3: — Chemical Kinetics — - Christian-Albrechts ...

2.7 Temperature dependence of rate coefficients 36
or 21
ln
(1 ) = −
(2.164)
I
Figure 2.14: Derivation of the Arrhenius equation.
I Experimental determination of E (see Fig. 2.14): Aplotofln vs. 1 gives
a straight line with slope −
I Integration of Eq. 2.156: Assuming that is independent of ,Eq.2.156canbe
integrated:
ln =
(2.165)
2
y
ln = −
+ (2.166)
y
( )= −
(2.167)
Equation 2.167 is used to represent ( ) over a limited -range using the two parameters
and :
• = Arrhenius activation energy (measure for the energy barrier of the reaction)
• = pre-exponential factor (frequency factor, collision frequency).
21
y
(1 )
= − 1
2 (2.162)
= − 2 (1 ) (2.163)