文档介绍：物理化学电子教案—第5章
Chemical Equilibrium
Chapter 5 Chemical equilibrium
The conditions of chemical equilibrium
and affinity of chemical reaction
The equilibrium constant of a reaction and
isothermal equation
Heterogeneous chemical equilibrium
Determination of equilibrium constants
The standard Gibbs function of formation
Contents
Coupling reaction
Chemical equilibrium of simultaneous reaction
The response of reactions to the conditions
Express mathematically how the equilibrium constant depends on the temperature, and derive and use the van’t Hoff equation.
Chemical reactions
We have seen that the natural direction of all change at constant temperature and pressure is towards minimum Gibbs function.
The idea is entirely general, and in this chapter we use it as a basis for the discussion of chemical transformations.
Consider the reaction A+B C+D
Is the natural tendency for the mixture A+B to go to the mixture C+D, or the opposite? This can be answered by calculating the Gibbs function of each mixture.
If the sum of the Gibbs functions of A+B is higher than that of C+D, then the reaction has a tendency to roll from left to right.
Chemical reaction system
Suppose a reaction:
Based on extent of reaction:
Or:
Fundamental equation
At const. T and P,
:
The reaction spontaneously
proceeds from left to right.
The reaction spontaneously
proceeds from right to left.
The reaction is at equilibrium.
Direction and limit of a chemical reaction
Use
to determine:
From left to right
From right to left
At equilibrium
Direction and limit of a chemical reaction
is the slope of G with recpect to the extent of reaction .
Direction and limit of a chemical reaction