Question

at 1500 celcius the system 2NO<-->N2+O2
was allowed to come to equilibrium. the equilibrium concentrations were
NO=0.00035M
N2=0.040M
O2=0.040M
What is the value of Kc for the system at this temperature?

The answer they give is 1.3 x10^4

Im getting 2.2 x10^-1 i don't know what im doing wrong.

Answer 1

I tried several combinations to get your answer and couldn't do it so I don't know what you're doing wrong either. The correct way to do it is as follows:
Kc = (N2)(O2)/(NO)^2 =
*0.04)(0.04)/(0.00035)^2 = 13,061.22 which rounds to 1.3E4 to two significant figures.

Answer 2

THANKS