Solutions of the Problems
1. The rate constant of the unimolecular process A ! products is the reverse
lifetime of the species A.
2. The rate constant of the bimolecular process A 1 + A 2 ! products is the process
rate at the A 1 , A 2 species unit concentrations.
3. The rate constant of the termolecular process A 1 + A 2 + A 3 ! products is the
process rate at the A 1 , A 2 , A 2 species unit concentrations.
4. Reaction orders and reagent orders can be zero or fractional. One can use
termolecular recombination A þ B
ðMÞ
! AB as an example. The reaction order
relative to [M] can be fractional or equal to zero, and reaction order decrease
from 3 to 2 with [M] increase.
5. One should divide 3Á10
14
Áexp(− 4.8 (KJ/mol)/RT) cm
3 /molÁ1 by Avogadro’s
number N A = 6.022Á10
23 mol
−1 , and take into account that 1 cal = 4.184 J,
R = 1.9858 cal/mol. Rate constant is 7.4Á10
–11 cm
3 /species s.
6. One should divide 3Á10
14
Áexp(- 4.8 (KJ/mol)/RT) cm
3 /molÁ1 by Avogadro’s
number squared, and take into account that 1 cal = 4.184 J,
R = 1.9858 cal/mol. Rate constant is 3.3Á10
–34 cm
6 /species
2 s.
7. A stoichiometric reaction order is equal to the sum of the stoichiometric coefficients in the stoichiometric equation, whereas a kinetic (real) reaction order is
equal to the sum of reaction kinetic order regarding species which take part in a
reaction. The kinetic (real) reaction order can be less than the stoichiometric one
(see solution of problem 4).
8. The equilibrium rate constant of the reaction (1)
Cl
2 P 3=2
À
Á þ Cl
2 P 3=2
À
Á $ Cl 2 X
1 R
þ
g
;
ð1Þ
© Springer Nature Switzerland AG 2021
A. Pravilov, Gas-Phase Photoprocesses, Springer Series in Chemical Physics 123,
https://doi.org/10.1007/978-3-030-65570-9
285