./
./
2
3
270 10
540 10
rate
rate
mole liter sec
mole liter sec
7
7
#:
= #:
..
..
k
k
0 100 0 010
0 200 0 010
MM
MM
nm
nm
=
^^
^^
hh
hh
= 2.00 = (2.00)nn= 1
rate = k[NO 2 ]^1 [Cl 2 ]^1
(b) Restatement: Overall order. Explain.
overall order = m + n = 1 + 1 = 2
The rate is proportional to the product of the concentrations of the two reactants:
2 NO 2 (g) + Cl 2 (g) →2 NO 2 Cl(g)
rate t k
NO
∆ NO Cl
∆ 2
= 22
- =
6
66
@
@@
or
rate t k
Cl
∆ NO Cl
2 ∆ 2
= = 22
- 6
66
@
@@
(c) Restatement: Rate-specific constant k.
rate = k[NO 2 ][Cl 2 ]
k= rate / [NO 2 ][Cl 2 ]
..
.
0 100 0 005
135 10
mole liter mole liter
mole liter sec
11
711
::
= #::
--
---
__ii
= 2.7 × 10 –4liter/mole ⋅sec
(d) Restatement: In experiment 3, initial rate of decrease of [Cl 2 ].
2 NO 2 (g) + Cl 2 (g) →2 NO 2 Cl(g)
d
dt
d
dt
Cl NO Cl
2
- 6622 @@= (^1) dn
= –(5.40 × 10 –7) / 2
= –2.7 × 10 –7mole ⋅liter–1⋅sec–1
(e) Restatement: Possible mechanism.
The proposed mechanism must satisfy two requirements:
(1) The sum of the steps must give a balanced equation.
(2) The mechanism must agree with the experimentally determined rate law.
NO 22 ____ggiiii++Cl k^1 NO Cl 2 ggCl slow
Cl___ggiii+NO 22 k^2 NO Cl gfast
Part II: Specific Topics