The balanced equilibrium reaction is:
N2(g) + O2(g) ---> 2NO(g)
Kc = [NO]2 / [N2] [O2] = (0.5
)2 / 0.1 X 0.1 = 25
Now the new concentration of NO in the system is 0.8 M
Let us see the changes through ICE table
                            Â
N2(g) + O2(g) ---> 2NO(g)
initial                    Â
0.1Â Â Â Â Â Â Â Â Â
0.1Â Â Â Â Â Â Â Â Â Â Â
0.8
Change                 Â
+x          Â
+x           Â
-2x
Equilibrium          Â
0.1+x        0.1
+x       0.8-2x
Kc = [NO]2 / [N2] [O2] = 25
25 = (0.8-2x)2 / (0.1+x)(0.1+x)
5 = 0.8-2x / 0.1+x
0.5 + 5x = 0.8 -2x
7x = 0.3
x = 0.0429 M
Therefore [NO] after equilibrium = 0.8-2x = 0.8- 2(0.0429) =
0.7142 M
