For each cell write the anode half reaction and the cathode half reaction. from the measured voltages, calculate the half-cell potentials for the lead and tin half-cells and the equilibrium constants for these two reactions. in these calculations, use e° = 0.34 v for the cu2+/cu couple.
cells:
cu/cu^2+ and pb/pb^2+: 0.506 v
cu/cu^2+ and sn/sn^2+: 0.689 v
pb/pb^2+ and sn/sn^2+: 0.190 v

it is the most commonly accepted one

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally