Consider the system
CO₂(g) + H₂(g) :rarrow: CO(g) + H₂O(g)
Initially, 0.25 mol of water vapour and 0.2 mol of carbon monoxide are placed in a 1.00 L reaction vessel. At equilibrium, spectroscopic evidence shows that 0.1 mol of carbon dioxide is present. Calculate K for the reaction.
So writing down the equilibrium law we get.
Kc = [CO][H₂O]/[CO₂][H₂]
Now we need to find the unknowns. We know 3/4 of the reaction's concentrations but how do you find the forth? An ice table wont work since we don't have a Kc value and without a given H₂ value we can't calculate Kc. Stoichometry sounds useless since the system is in equilibrium so what the heck. How do you solve this problem?