Equilibrium Formation

Completion (stoichiometric end-state)

• Choose $\xi$ to exhaust limiting reactant: products are as written; by construction no backward reaction considered.
• Useful for quick energy estimates (e.g., heating value) when dissociation is negligible.

Equilibrium Formation

• Use $K(T)$ and atom balances to find ${\xi }_{\ast }(T,p)$ (or full $\{x_i\}$).
• At high $T$ and moderate $p$, dissociation reduces stable product mole fractions vs. completion (e.g., $\mathrm{CO}{}_2$ splits to $\mathrm{CO}$ and $\mathrm{O}{}_2$ traces).

Implication: adiabatic flame temperature and performance must reference equilibrium (unless conditions ensure negligible dissociation).