how do you find the pressure in equilibrium?

Question

the equilibrium 2 n2+o2=2n2o has a keq = 8.41x10^-8 at 25°c.If 0.54 atm of N2(g) and 0.27 atm of O2(g) are injected into a flask determine the equilibrium pressures of all gases

Answer 1

Chemical symbols should be in upper case, as there is no such thing as n2 for example.  Written in the correct manner, you have 2N₂ + O₂ ==> 2N₂O with a Keq = 8.41x10^-8

Set up an ICE table as follows:

.........2N₂ + O₂ ==> 2N₂O

I.......0.54....0.27......0.....

C....-2x......-x.........+2x......

E...0.54-2x...0.27-x.......2x...

Keq = (P_N2O)²/(P_N2)²(P_O2) = 

8.41x10^-8 = (2x)²/(0.54-x)²(0.27-x)

Solve for x

Equilibrium pressures will be 2x for N2O; 0.54-2x for N2 and 0.27-x for O2