Page 149 - Bruno Linder Elementary Physical Chemistry

August 18, 2010 11:37 9in x 6in b985-appA Elementary Physical Chemistry

134 Elementary Physical Chemistry

obeys the following rules

−
H 2 O 2 (aq) + Br (aq) → H 2 O(l) + BrO − (slow)
−
−
BrO (aq) + H 2O 2 (aq) → H 2O(l) + O 2 (g) + Br (aq) (fast)
Determine the reaction rate, r, and the order of the reaction with
respect to H 2 O 2 and with respect to Br .
−
16. A reaction is found to obey the following mechanism.
A 2 2A (rapid equil.)
A+B → P (slow)
What is the rate law for the formation of P?
17. The mechanism for a chain reaction involving free radicals obeys the
following rules:
k a
i. [MN] −→[M • ]+ [N • ]
k b
ii. [M ] −→[O ]+ [Q]
•
•
k c
iii. [MN] + [O • ] −→[M • ]+ [R]
k d
iv. [M • ]+ [O • ] −→[P]
The k a , k b , k c , k d are the reaction constants of the chain reactions.
What is the reaction order with respect to [MN]?

Problem Set VI. Chapters 8, 9
1. If the wavelength of an electron is 500 × 10 −12 m, what is its velocity?
[The electron mass is m e =9.1094 × 10 −12 kg; Planck’s Constant is
2 −2
h =6.626 × 10 −34 Js; 1J = 1 kg m s .]
2. A photon knocks an electron out of an atom. If the ionization potential
6
of the atom is 2.5 × 10 −18 J and the speed of the electron is 10 ms −1 ,
what is the frequency of the incident photon?
3. If the uncertainty in position of a particle moving with a momentum
of 5.0 × 10 −20 kg m s −1 is ∆x =9.0 × 10 −10 m, what fraction is the
uncertainty in speed, ∆p, of the actual momentum of the particle?
4. A hydrogen atom in a one-dimensional box of length L =10 −9 m jumps
from level 3 to level 2. How much energy is released?
5. An electron in a one-dimensional box of length L =5.0 × 10 −9 makes
a transition from level 5 to level 3.
(a) What is the energy release for this process?
(b) What is the wavelength of the emitted radiation?