Calculate Keq when equilibrium is achieved ?

ICE Table! Set up your ICE table with .24 molarity NO2 as initial, and 0 molarity initial for NO and O2. Then to get an equilibrium of .14 for NO, you need to add .14 molarity for NO, .07 molarity for O2, and -.14 molarity to NO2. This leaves us with .1 molarity NO2 at equilibrium, .14 molarity NO at equilibrium, and .07 molarity O2 at equilibrium. The Keq expression is [NO2] squared = [NO] squared X [O2]. Plug in the molarities for each and the answer is 1.4 X 10 ^-1!