Equilibrium constant question?

[Raul3140]

Equilibrium constant question?

Homework Statement

A mixture of 0.229 mol CO2, 0.229 mol of H2, and 0.328 mol of H2O are placed in a 2.0 L container. The following equilibrium is established:
CO2 + H2 <-> CO + H2O. The equilibrium concentration of H2O is 0.210 M. Calculate the equilibrium constant (Kc)

Homework Equations

Kc=Products/reactants...raised to their stochiometric coefficients.

The Attempt at a Solution

I keep getting 2.011 I used the stochiometric relationship to determine the changes in concentration.

The answer is supposed to be 2.06

 

[epenguin]

I got 2.06 , or 2.0587 to be exact.

If you are that close you have probably not made any great mistake of principle.

Have you carried through the arithmetic to full precision at each stage?

Your equilibrium [CO₂] and [H₂] are equal? (0.0685 M)

One thing you may find profitable is instead of going through your work, you totally recalculate without looking at it. It goes a lot faster this time which boosts confidence. But perhaps you have already done that.
If there is a small arithmetical error only it will lose you very few marks if any in most sensible exams etc.

Checking whether your equilibrium [H₂] + [H₂O] adds up to the initial sum as it should, and similarly for the other pair might localise any error.
[CO] = 0.046 M