(3)
However, we have many A molecules present at a concentration , (molecule/dm3). Adding up the collisions of all the A molecules per unit volume, , then the number of collisions of all the A molecules with all B molecules per time per unit volume is
(4)
Where Sr is the collision cross section (Å)2. Substituting for Sr and UR
[molecules/time/volume] (5)
If we assume all collisions result in reactions then
[molecules/time/volume] (6)
Multiplying and dividing by Avogadrósnumber, NAvo, we can put our equation for the rate of reaction in terms of the number of moles/time/vol.
(7)
(8)
where A is the frequency factor
(9)
(10)
Calculate the frequency factor A for the reaction
at 273K.
Additional Information
Using the values in Table PRS.3A-1
Collision Radii
Hydrogen H H=2.74 Å/4 = 0.68Å = 0.68 x 10–10m
Oxygen O2 Å 1.55Å = 1.5 x 10–10m
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