Page 301 - Elements of Chemical Reaction Engineering 3rd Edition

Chap. 5 Questions and Problems 273

TABLE P5-10 RAW DATA
Ozone Butene
Ozone Rate Concentration Concentration
Run (moUs. dm3 X lo7) ( mol/dm3) (moUdm3)
1 1.5 0.01 10-12
2 3.2 0.0% 10-1'
3 3.5 0.0 I5 10;'O
4 5 .O 0.005 10-9'
5 8.8 0.001 10-8
6 4.7 O.OL8 10-9
(Hint: Ozone also decomposes by collision with the wall)

P5-11, Tests were run on a small experimental reactor used for decomposing nitrogen
oxides in an automobile exhaust stream. In one series of tests, a nits-ogen
stream containing various concentrations of NO, was fed to a reactor and the
kinetic data obtained are shown in Figure P5-11. Each point represents one
comple1.e run. The reactor operates essentially as an isothermal backmix reac-
tor (CSTR). What can you deduce about the apparent order of the reaction
over the temperature range studied?
The plot gives the fractional decomposition of NO, fed versus the ratio
of reactor volume V (in cm3) to the NO, feed rate, FNo2,,(g molh), at differ-
ent feed, concentrations of NO, (in parts per million by weight).

.T = 300' C

PPm NO2 in feed
0 1896 Ppm NOp in feed
V 3050 PPm NO2 in feed

0 1 2 3 4 5

Figure P5-11
P5-128 Microelectronic devices are formed by first forming SiO, on a silicon .wafer
by chemical vapor deposition (Figure P5-12; cf. Problem P3-25). This proce-
dure is fiollowed by coating the SiO, with a polymer called a photoresist. The
pattern of the electronic circuit is then placed on the polymer and the sample
is irradiated with ultraviolet light. If the polymer is a positive photoresist, the
sections that were irradiated will dissolve in the appropriate solvent and those
sections not irradiated will protect the SO, from further treatment. The wafer
is then exposed to strong acids, such as HF, which etch (ie., dissolve) the