Topic 7a - Bimolecular Reactions
Topic 7a - Bimolecular Reactions
Topic 7a - Bimolecular Reactions
Note:
Rate Constant
where:
Z = collision frequency.
= steric factor.
Ea = activation energy of the reaction.
T = absolute temperature (K).
R = gas constant.
K + Br2 KBr + Br
Process:
i. K atom approaching a Br2 molecule, when the two
are close enough, the valence electron (the harpoon)
flips across from K to Br2. Such a transfer is possible
even when the reactants are far apart (5 10 ).
ii. In place of two neutral particles, there are now two
ions, and so there is a strong Coulombic attraction
between them: this attraction is the line on the
harpoon.
iii. Under its influence the ions move together, the
reaction takes place, and KBr + Br emerge.
Harpoon Mechanism:
= IE EA = E