Posted by Paul on .
At T = 25 degrees Celsius, the reaction No2 <> 2NO +O2 has an equilibrium constant K=5.0*10^13. Suppose the container is filled with NO2 at an initial pressure of 0.25 atm. Calculate the partial pressure of NO at equilibrium

Chemistry 
DrBob222,
I assume that K listed is Kp and not Kc. Note that your equation is not balanced.
........2NO2 > 2NO + O2
I.......0.25......0.....0
C........2x......2x.....x
E.......0.252x....2x......x
Kp = pNO^2*pO2/pNO2^2
Substitute and solve for x and 2x