The effect of activation energy on reaction rate

2.
The effect of activation energy on reaction rate

For the formula

If you draw a graph with 1gk pairs, you will get a straight line in the rectangular coordinate system.

Figure 3-4 shows the relationship between temperature T and rate constant k
.

Figure 3-4 The relationship between temperature and rate constant

For example, if the activation energy E _a =50kJ·mol ^-1 , the reaction temperature increases from 400K to 420K, and the ratio of k ₂ to k ₁ is 2.

From the rate constants at two temperatures, the activation energy Ea of the reaction can be directly calculated
.

The direct calculation of the activation energy from the above formula only involves two experimental points, which has a larger error than the activation energy obtained by the mapping method, because the mapping method involves multiple experimental points
.

[Example 3-4] The rate constant of a reaction at 300K is 9.

(1) The activation energy E _{a of the} reaction ;

(2) Rate constants at 310K and 330K;

(3) The rate constant increases for every 10K increase in temperature
.

(2) Substitute the known data

Example 3-4 The calculation results show that for every 10K increase in temperature, the reaction rate increases by 2 to 4 times, which shows that Vanter Hoff's law is experimentally based