I'm clueless on this take-home quiz we have.

Question

Calculate the concentration of (Co3)2- in a solution made by dissolving 1 mole of Co2 in 1 L of water. The hydration equilibrium constant Kh of Co2 at 25C is 1.70x10-3, Ka1 of H2CO3=2.5x10^-4, and Ka2=5.01x10^-11.