This problem is a fairly simple single$-$reaction equilibrium which can be solved without numerical iteration. The K value can be sourced from Fundamental of Engineering thermodynamics textbook table A$-27.$ Question: As an approximation to the conditions within an internal combustion engine, consider the equilibrium reaction N $+$O $2$ NO occurring in air alone at $1500$ K and $11$ bar. Calculate the $$ equilibrium mole fraction of NO under these conditions.