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Chapter 8

Chemical Kinetics I: Basic Kinetic Laws

RATE OF A REACTION
Any chemical reaction may be represented by the stoichiometric
equation
UAA + UBB + . . . 4 UCC+ UDD + . . .

where uA, uB, vc and UD are termed the stoichiometry factors.
Chemical kinetics is concerned with the rate at which reactions
proceed. The rate of a chemical reaction is a measure of how fast the
products (C, D, . . .) are formed and how fast the reactants (A, B, . . .)
are consumed. The rate of a chemical reaction is related to the
stoichiometry. Consider the reaction:
A + 4B + 3C + 2D
where UA = 1, VB = 4, uc = 3 and VD = 2.

-- d[A1 = rate of decrease of [A]
dt
-- d[B1 = rate of decrease of [B]
dt
+- = rate of increase of [C]
d[CI
dt
rate
=
+a of increase of [D]
dt
where the rate is proportional to the reciprocal of time, i.e. l/time or
d/dt expressed as a derivative.