...and label a diag? Calculate E for the spontaneous cell using the Fe3+, Fe2+, Cu2+, and Cu couples. Draw and label a diagram of hte cell and write the equation for the balanced reaction. show the direction of flow for the electrons and ions. Assume chloride salts. What happens to the cell voltage when 1 M KSCN is added to the cathodic compartment of the cell? Explain why.