A copper, Cu(s), electrode is immersed in a solution that is 1.00 M in ammonia, NH3, and 1.00 M in tetraamminecopper(II), [Cu(NH_3)_4]^{2+}. If a standard hydrogen electrode is used as the cathode, the cell potential, E_cell, is found to be 0.076 V at 298 K.
Based on the cell potential, what is the concentration of \rm Cu^{2+} in this solution?