Question

Describe an experimant that would enable you to determine which is the cathode and which is the anode in a galvanic cell using copper and zinc electrodes.

Answer 1

Set up a basic electrochemical cell.

To determine quantitatively;
Measure and record the mass of the zinc electrode (E1) then the copper electrode (E2)
Fill each beaker with each electrolyte (solution containing each half-cells respective aqueous metal ions) I would suggest Zinc Chloride, ZnCl_2, (S1) and Copper Sulfate, CuSO_4, (S2)
Use at least 2M electrolytes, the higher the concentration the faster the rate of reaction.
Use a suitable salt bridge, usually Potassium Nitrate, KNO_3, (S.B)
Then connect the two half cells with the voltmeter/wire
Allow the reaction to proceed for some time and then disconnect the cells and remeasure the mass of each electrode.
Reduction occurs at the cathode, and oxidation at the anode, since the aqueous metal ions are both cations whichever one is being reduced will change from a +2 oxidation state to a 0 oxidation state, so it will be reduced to the metal therefore which ever electrode gains mass is where reduction has occurred and will have gained mass.

To do the same to determine observationally, simply take note of which beaker is gaining small metallic flakes, could look like a precipitate, that is also the cathode.