CHAP. 8: CHEMICAL EQUILIBRIUM [CONTENTS] 226
Chapter 8
Chemical equilibrium
This chapter deals with systems in which chemical reactions take place. In the course of a chem-
ical reaction, the composition of the reacting system approaches its equilibrium composition.
The rate at which this equilibrium can be attained is dealt with by another field of physical
chemistry, chemical kinetics [see 9 ]. Calculations of the equilibrium composition and the effect
of temperature, pressure and non-reacting components on the composition of a system in the
state of chemical equilibrium are described in this chapter for one reaction. The process of
this calculation for more simultaneously proceeding reactions is described at the close of the
chapter.
8.1 Basic terms
- Chemical reactionis a process [see1.4.3] during which new aggregates of atoms are
formed in consequence of a collision (radiation,... ).
Note: In thermodynamics, phase transformations, e.g. C (graphite) = C (diamond), are
sometimes ranked among chemical reactions.- Chemical equilibriumis a special case of thermodynamic equilibrium [see1.4.1and
1.4.2].