kc, equilibrium question:....thx =)?

Question

equation:

H2(g) + CO2(g) <===> H2O(g) + CO(g)

question:

Kc = 5.84 at 1510K. If each of the four species was initially present at a concentration of 6.000M, calculate the equilibrium concentration of the CO(g) at this temperature.

answer could be...

2.488
9.761
9.337
8.488
3.512

Answer 1

H2(g) + CO2(g) <===> H2O(g) + CO(g)
I 6.00 6.00 6.00 6.00
C -x -x + x +x
E (6-x) (6-x) (6+x) (6+x)


Kc =5.84
[CO][H2O]/[H2][CO2] = 5.84
(6+x)^2/(6-x)^2 =5.84
(6+x)/(6-x)=2.4166
14.50-2.4166x = 6 +x
x = 2.48775
thus [CO] = 6.00 + 2.48775 = 8.488 M(ans)

Answer 2

(6 + x)squared/(6 - x)squared = Kc

(6 + x)/(6 - x) = root Kc.

Now solve for x.