Your 0.0158 is not Kc because you have substituted the INITIAL concns. You are supposed to substitute equilibrium concns. I would look at this way.
........CH4 + H2O ==> ..CO +.... 3H2
init..0.9530..0.9911..0.7474...0.2717
change....-x.....-x.......+x.....+3x
eq.0.9530-x..0.9911-x..0.8584.0.2717+3x
So you get x by 0.8584-0.7474 = 0.1110
which allows you to find all of the other equilibrium concns. Substitute those to obtain Kc.
The initial concentration for the compounds involved in the reaction displayed were determined to be [CH4(g)] = 0.9530 mol/L, [H2O(g)] = 0.9911 mol/L, [CO(g)] = 0.7474 mol/L, [H2(g)] = 0.2717 mol/L. Calculate the value of the equilibrium constant (Kc) at 1200 K if the equilibrium concentration of CO(g) was 0.8584 mol/L.
CH4(g)+H2O(g) = CO(g)+3H2(g)
i know to find Kc you have to do the products over reactants like this:
([H2]^3)([CO]) / ([CH4][H2O])
and i did the difference of 0.854 & 0.7474 for CO to get it but the answer is still not right..
the answer is 0.2561
but i keep getting 0.0158
i dono what im doing wrong..
**thanks for the help btw!!!
1 answer