Calculating KC Given Equilibrium Concentrations Ex. N2O4(g) 2NO2(g)
• If you place 0.0350 mol N2O4 in 1 L flask at
equilibrium, what is KC?
• [N2O4]eq = 0.0292 M
• [NO2]eq = 0.0116 M

i want to know from where this coming

• [N2O4]eq = 0.0292 M

• [NO2]eq = 0.0116 M
Those are the concentrations of $\mathbf{N_2O_4}$ and $\mathbf{NO_2}$ at equilibrium. They are just given to you as part of the question for you to use in calculating $K_c$.