Final answer:
The equilibrium constant expression for the combustion of propane (C₃H₈ + 5 O₂ ↔ 3 CO₂ + 4 H₂O) is Kₒ = (PCO₂)3 × (PH₂O)4 / (PC₃H₈) × (PO₂)5, using partial pressures of the gases involved.
Step-by-step explanation:
The balanced chemical equation for the combustion of propane is
C₃H₈(g) + 5 O₂(g) ↔ 3 CO₂ + 4 H₂O(g).
The equilibrium constant expression for a reaction is written as the product of the concentrations of the products raised to the power of their stoichiometric coefficients, divided by the product of the concentrations of the reactants raised to the power of their stoichiometric coefficients.
For reactions involving gases, we use partial pressures, denoted as P, in place of concentrations.
The equilibrium constant expression for the combustion of propane (in terms of partial pressures) is:
Kₒ = (PCO₂)3 × (PH₂O)4 / (PC₃H₈) × (PO₂)5
It is important to note that water (H₂O) is in the gaseous state in this reaction as indicated by its phase in the chemical equation, and therefore, it is included in the expression.