__Chemical Kinetics__ - The study of
the rates of chemical reactions.

__Rate of a Reaction__ - The change
in concentration of one of the reactants (DX),
during a given period of time (Dt)

The reaction rate gradually decreases as reactants are consumed.
__Instantaneous Rate of Reaction__
- The rate of a reaction at an instant in time.

where d(X)/dt is the derivative X/t in terms of t.
__Rate Law__ - An equation that describes
how the rate of a chemical reaction depends on the concentrations of the
reactants consumed in that reaction.
**rate = k[O**_{3}]
__Rate Constant (k) __- The proportionality
constant in the rate law equation that describes the relationship between
the rate of a step in a chemical reaction and the product of the concentrations
of the reactants consumed in that step.

**The rate law for a reaction cannot be determined by
the coefficients of the balanced reaction; it must be determined experimentally.

For gas equilibrium equations, the equilibrium constant (K_{c})
is equal to the rate constant for the forward reaction divided by the rate
constant of the reverse reaction.
See Sample Rate Calculations

For the reaction:
where a, b, c, d are the coefficients for the reactants and products A,
B, C, D
Next: "Order and Molecularity"