Biomedical Engineering Reference
In-Depth Information
PROBLEMS
7.1. At 518
C, acetaldehyde vapor decomposes into methane and carbon monoxide
according to CH
3
CHO
CO. In a particular experiment carried out in
a constant-volume BR (Hinshelwood and Hutchison, 1926), the initial pressure of
acetaldehyde was 48.4 kPa, and the following increases of pressure (
CH
4
þ
/
D
P
) were noted
(in part) with increasing time:
t
, s
42
105
242
480
840
1440
D
P
, kPa
4.5
9.9
17.9
25.9
32.5
37.9
From these results, determine the order of reaction and calculate the value of the rate
constant in pressure units (kPa) and in concentration units (mol L
1
).
7.2. Rate constants for the first-order decomposition of nitrogen pentoxide (N
2
O
5
) at various
temperatures are as follows (Alberty and Silbey, 1992, p. 635):
T
, K
273
298
308
318
328
338
k
,10
5
s
1
0.0787
3.46
13.5
49.8
150
487
Show that the data obey the Arrhenius relationship and determine the values of the
Arrhenius parameters.
7.3. The oxidation of propene to acrolein was carried out over a Mo-Pr-Bi Catalyst [
Ind. Eng.
Chem. Res.
, 26, 1419(1987)].
CH
3
CH
[
CH
2
DO
2
/
CH
2
[
CHCHODH
2
O
It has been proposed to correlate the data using the power-law model for the rate law.
r
acrolein
¼ kp
P
p
O
2
The reaction was carried out in a differential reactor with 0.5 g catalyst at 623 K. From the
data below, determine the reaction orders with respect to propene and oxygen and the
specific reaction rate.
F
A
, mmol/h
0.21
0.48
0.09
0.39
0.60
0.14
1.44
p
P
, atm
0.1
0.2
0.05
0.3
0.4
0.05
0.5
p
O
2
, atm
0.1
0.2
0.05
0.01
0.02
0.4
0.5
where
F
A
¼
exiting molar flow rate of acrolein,
p
P
¼
entering partial pressure of propene,
and
p
o
2
¼
entering partial pressure of oxygen.
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