Heterogeneous Equilibria Reactions Involving Solids and Liquids

5 Heterogeneous Equilibria Reactions Involving Solids and Liquids 

Many chemical reactions involve pure solids or pure liquids as reactants or products. Consider, for example, the reaction  

Similarly, the concentration of a pure liquid does not change. So, pure liquids—reactants or products labeled in the chemical equation with an ( )— are also excluded from the equilibrium expression. For example, consider the equilibrium expression for the reaction between carbon dioxide and water  

Since H20( ) is pure liquid, it is omitted from the equilibrium expression  

FIGURE 14.6 Heterogeneous Equilibrium The concentration of solid carbon (the number of atoms per unit volume) is constant as long as some sohd carbon is present. The same is true for pure bquids. For this reason, the concentrations of solids and pure liquids are not included in equihbrium constant expressions. 

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