PHYSICAL CHEMISTRY IN BRIEF

CHAP. 8: CHEMICAL EQUILIBRIUM [CONTENTS] 233

equilibrium

equilibrium

Obr.8.1:Dependence of the Gibbs energy of a closed system on the extent of reaction.

U Main unit: J mol−^1.
TheGibbsorreaction isothermis the relation between the change in the Gibbs energy
(at one mole of reaction at constant temperature and pressure) and the activities of the reacting
substances (which change in the course of the reaction).

∆rG= ∆rGst+RTln

∏k

i=1

aνii. (8.10)

∆rGst=

∑k

i=1

νiμsti =

∑k

i=1

νiGstm,i (8.11)

is the change in the Gibbs energy at one mole of reaction if substances involved in the reaction

are in a standard state [see5.2].

S Symbols:The symbol

∏k

i=1a

νi

i denotes the product of the activities of substances from 1 tok,

raised to the power of their stoichiometric numbers.