a. A cell constructed with a Zn | Zn2 half-cell and a Al |Al3+ half cell 1. Determine Ecell (V) 2. Write the net ionic equation for the cell (see directions above - pay special attention to Step 7) Work Problem 3. Identify the half-cell at the cathode (enter a number 1 - 4) 1. Zn2+ (aq)+2 eZn°s 2. Zn(s)Zn2* (aq) 2 e +3 eAl(s) 3. Al3+ (aq) 4. Al A3+ 3 e (aq) 2. Use a table of Standard Electron Reduction Potentials (click the Reference Materials link in the header of this webpage and then the Standard Reduction Potentials link) to determine the E° for the following standard cells. Write the net ionic equation for the cell. Identify which half-cell will be the cathode. Directions For Writing Molecular, lonic, And Net lonic Equations: 1. Molecular Equation: balance the molecular equation by predicting the products and changing the coefficients so that all atoms are balanced. Equations must be balanced to obey the Law of Conservation of Matter 2. lonic Equation: the ionic equation is obtained by breaking apart into ions any strong acid, strong base or soluble salt that has an (ag) after its formula - the ion's new coefficient will equal the coefficient (from the balanced equation) TIMES the ion's subscript (i.e. 2 Na2SO4 becomes 4 Na* and 2 SO42-). 3. Do Not Break Apart any reactant or product that has an (s) or () or (g) after its formula - list it exactly as it appears in the molecular equation 4. Do Not Break Apart a weak acid or base that has an (aq) after its formula - by definition a weak acid (or base) is not 100% ionized so it is represented as a molecule and not as ions. 5. Net lonic Equation: write the net ionic equation by cancelling out any spectator ions (ions that appear on both sides of the equation) and simplifying the coefficients to the smallest whole number ratio (if necessary). 6. Make sure to include the charge and state for the ions and molecules - all molecules have a charge of zero. 7.As a final check, the total charge on the reactant side must equal the total charge on the product side - this fact will aid you in writing Red Ox (Reduction Oxidation) reactions.