CHAP. 9: CHEMICAL KINETICS [CONTENTS] 296
Example
Consider the same reactions as in the preceding example:
A →k^1 R + 2S + B, (1)
A + B
k 2
→ M + S. (2)
The initial concentrations of substancesAandBarecA0andcB0. The initial concentrations of
the other substances participating in the reactions are zero. Write the material balance equations
for all substances involved in the reactions.
Solution
cA = cA0−x 1 −x 2 ,
cB = cB0+x 1 −x 2 ,
cR = x 1 ,
cS = 2x 1 +x 2 ,
cM = x 2.
9.4.4 First-order parallel reactions.
9.4.4.1 Type of reaction
A
k 1
→ B,
A
k 2
→ C.
9.4.4.2 Kinetic equations.
dcA
dτ
= −(k 1 +k 2 )cA, (9.96)
