The problem states:
Methanol, CH3OH, is produced commercially by the catalyzed reaction of carbon monoxide and hydrogen: CO(g) + 2 H2(g) CH3OH(g). An equilibrium mixture in a 2.00 L vessel is found to contain 0.0406 mol CH3OH, 0.170 mol CO and 0.302 mol H2 at 500. K. Calculate Kc at this temperature.
I have no idea how to go from moles to the partial pressure, but once i have that I can find out Kc.