To find the equilibrium concentration of NO in the reaction N2 + O2 = 2NO, start by establishing the equilibrium expression based on the reaction stoichiometry. Given 10 moles of N2 and 1 mole of O2, determine the initial concentrations before the reaction shifts to equilibrium. The equilibrium constant can be expressed in terms of partial pressures, which will help in calculating the concentration of NO. It's essential to set up an ICE (Initial, Change, Equilibrium) table to track the changes in concentrations. The final goal is to calculate the concentration of NO in ppm at equilibrium.