|Heterogeneous Reaction Systems
|A system that has two for more phases is heterogenous.
|eg. CaCO3(s) + dil. HCl
CO2(g) + CaO(s)
|Increasing the amount of solid present in a heterogenous
increases the total, surface area at which both the forward and reverse
reactions are occurring. The total number of moles of solid reactant
converted into product per unit time increases. However, the total
of moles of product being converted back into reactant increases
This results in no net change in the total amount of reactant or
|Therefore Keq for the above reaction is
the [CO2] only.
|ie. the Keq equation for the above reaction is
= [CO2] only.
|The equilibrium constant expression for a heterogeneous
involving gases does not include the concentrations of pure
|eg. NH4Cl(s) <====> NH3(g)
|Keq = [NH3][HCl]