[NewtoAtoms]

Q:  For the reaction

      H2 (g)  +  CO2 (g) <----------> CO (g) + H20 (g)

Kc = 0.771 at 750^oC.
Find the resulting concentrations of the H₂ and H₂O gases when 1 mol of H₂ and 1 mol of CO₂ are placed in a 5.00 L container and permitted to reach equilibrium. 

I have done the leg work, but I would just appreciate if someone checked to see if what I am doing is correct, so I can continue with the rest of the chapter, knowing the previous material.

STEP #1
                       H₂             CO₂    <---------->   CO         H₂0
Initial:              1 mol          1 mol                      O            O
Change:           -x               -x                         +x           +x
Equilibrium:     (0.2M -x)     (0.2M - x)                 +x            +x

I calculated 0.2M by the following:  x/1L = 1.00 mol/5.0L = 0.2M

STEP #2

Kc = [CO][H₂0] / [H₂][CO₂]

0.771 =  (x) (x) / [0.2-x][0.2-x] :  SQUARE ROOT EACH SIDE

0.878 = x / 0.2 - x

0.878(0.2-x)=x
0.1756 -0.878x = x
0.1756 = 1.878x
0.094 = X

IS THIS AT ALL CORRECT??

Thank you for your help.

[vhpk]

Well, that's correct