Page 445 - Elements of Chemical Reaction Engineering Ebook

41 6 Nonelementary Reaction Kinetics Chap. 7

(b) If this reaction is carried out in a CSTR that has a volume of loo0 dm3, to
which the volumetric flow rate is 3.2 dm3/min, determine the three possible
steady states, noting, if possible, which are stable. The entrance concentra-
tion of the substrate is 50 mm0i/dm3. What is the highest conversion?
(e) What would be the effluent substrate concentration if the total enzyme
concentration is reduced by 33%?
W-14, The following data on bakers' yeast in a particular medium at 23.4"C and var-
ious oxygen partial pressures were obtained:

Q,, (20 mg sulfanilamide/mL
Po* Q,, (no sulfanilamide) added to medium)
0.0 0.0 0.0
0.5 23.5 17.4
1 .o 33.0 25.6
1.5 37.5 30.8
2.5 42.0 36.4
3.5 43.0 39.6
5.0 43.0 40.0
P = oxygen partial pressure, mmHg; eo, = oxygen uptake rate,
pL 02 of O2 per hour per mg of cells.

(a) Caalate the Qo, maximum (Vmax), and the Michaelis-Menten constant
K,. (Am: V,, = 52.63 pL O,/h.mg cells.)
(b) By use of the Lineweaver-Burk plot, determine whether sulfanilamide is
a competitive or noncompetitive inhibitor to 0, uptake. (Refer to Prob-
lem W-12).
(University of Pennsylvania)
W-15 (a) Use the supplementary reading to give three examples each of polymers
formed by step polymerization and by chain polymerization. Describe
the monomers, structural unit@) and repeating unit in each case.
(b) Plot yj, wj as a function of j for degrees of polymerization of 5, 10, and
20. Plot Pto as a function of conversion of functional groups, p, for M, =
1 mol/dm3.
(c) Plot fi and wj as a function 'of j for free radical termination by combina-
tion for p = 0.8, p = 0.9 and p = 0.95.
(d) Determine the molecular weight distribution for the formation of polysty-
rene for an initiator concentration 0f_'0-' molar and a: monomer concen-
tration of 3 molar. What are an, M,, and the polydispersity, D, after
40 hrs? How would the an change if chain transfer were neglected?
(e) The polymerization of styrene is carried out in a batch reactor. Plot the
mole fraction of polystyrene of chain length 10 as a function of time for
an initial concentration of 3M and 0.01M of monomer and initiator
respectively. The solvent concentration is 10 molar.
W-lh The instantaneous number-average degree of polymerization, X,, can be
expressed as
zhl= moles monomer consumed/dm3 . s - -rM (P7-16.1)
dead polymer molecules produced/dm3 . s c r,
(a) Consider an additional termination step resulting from the combination
of the initiator molecule and a free radical R,: