Final answer:
The equilibrium constant expression for the reaction BaCO3(s) ⇔ BaO(s) + CO2(g) is given by Kp = P(CO2), as only gaseous components are included in the expression. Solids like BaCO3 and BaO do not appear in the equilibrium constant expression.
Step-by-step explanation:
Writing Equilibrium Constant Expressions
The reaction BaCO3(s) ⇔ BaO(s) + CO2(g) involves a solid reactant breaking down into another solid and a gaseous product. When writing an equilibrium constant expression for a reaction, it is important to remember that only the concentrations of gases and aqueous solutions are included. Solids and liquids do not appear in the expression because their concentration does not change in a closed system.
To write the equilibrium constant expression (Kp) for the given reaction in terms of partial pressure, we only include the gaseous CO2. The expression would be:
Kp = P(CO2)
Since BaCO3 and BaO are both solids, they do not appear in the expression.
Other Equilibrium Expressions:
- For N2(g) + 3 H2(g) ⇔ 2 NH3(g), the Kc expression would be: Kc = [NH3]^2 / ([N2] · [H2]^3)
- For CO(g) + O2(g) ⇔ CO2(g), the equilibrium constant expression is: Kc = [CO2] / ([CO] · [O2])
- For 2 CO2(g) ⇔ 2 CO(g) + O2(g), the expression is: Kc = ([CO]^2 · [O2]) / [CO2]^2