Page 128 - Introduction to chemical reaction engineering and kinetics

110 Chapter 5: Complex Systems

5-6 Suppose the liquid-phase decomposition of A takes place according to the following kinetics
scheme with rate laws as indicated:

A -+ B +E;rn = k,cA

Reaction is carried out isothermally in a batch reactor with only A present initially at a con-
CentdOn CA0 = 4 mol L-’ in an inert SOlvent. At t = 1200 s, CA = 1.20 mO1 L-’ and en = 0.84
mol L-l. Calculate (a) the values of kl and k2 (specify the units), and (b) the values of cu and
cE at t = 1200 s.
5-7 For reaction according to the kinetics scheme

A+ B + C;rn = klCA
A + D; q, = k*CA

data are as follows:

Assuming that only A is present at t = 0, and that reaction occurs at constant Tin a constant-
volume batch reactor, calculate xnt. kl and k2.
5-8 The following data are for the kinetics scheme:

A -*B+C;rn = k,CA
A -+ D; rn = k2CA

Assuming that reaction occurs in a constant-volume batch reactor at a fixed temperature, and
that at time zero only A and B are present, calculate (not necessarily in the order listed): (a)
kl and k,; (b) CA0 and cnO at time zero; (c) cu at 40 min; (d) ca at 20 min.
5-9 Suppose a substance B decomposes to two sets of products according to the kinetics scheme

h
B-P1 + . . . . kl = Al exp(-&t/RT)
B %P, + . . . ; k2 = A2 exp(-E&RT)

such that the rate laws for both steps are of the same form (e.g., same order). What is the overall
activation energy, EA, for the decomposition of B, in terms of the Arrhenius parameters for
the individual steps? (Giralt and Missen, 1974.)