Suppose 0.125 mol of SCN-(aq) is added to a 1.00 L beaker containing an unknown concentration of Co2+(aq). These two ions react according to the following equation, with an equilibrium constant of 1.0 x 103.

Co2+(aq) + 4 SCN-(aq) ⇌
Co(SCN)42-(aq)

If the equilibrium concentration of Co(SCN)42- is measured to be 6.3 x 10-3 mol L-1, what was the initial concentration of Co2+(aq)?



[Co2+]initial =
6.3E-6
mol L-1