Experiment Aim: To identify the conditions under which a galvanic cell is produced. Equipment: – beakers – copper electrode – filter paper – zinc electrode – electrical wires – copper sulfate – voltmeter – zinc sulfate – sodium nitrate Risk assessment: – Sodium nitrate is poisonous, so gloves must be worn when soaking the filter paper into it. Method: 1. Set up a simple galvanic cell using the equipment listed above and observe the voltage on the voltmeter. 2. Remove the salt bridge and note what happens to the salt bridge.
3. Replace the salt bridge and remove the copper electrode from the solution and observe the voltage. 4. Use two identical beakers (that is, have one copper electrode in copper sulfate solution and another copper electrode in copper sulfate solution).
Observe the voltage. 5.
Record your results. Results: Conditions of galvanic cell Voltage (V) – Zn electrode in ZnSO 4 solution- Cu electrode in CuSO 4 solution- NaNO 3 salt bridge 0. 55 – Zn electrode in ZnSO+4+ solution- Cu electrode in CuSO 4 solution 0 – Zn electrode in ZnSO 4 solution- NaNO 3 salt bridge 0 Identical beakers 0 Conclusion: The oxidation reaction at the anode is: The reduction reaction at the cathode is: Overall oxidation-reduction reaction (redox reaction): The cell diagram for the galvanic cell is: Zn (s) | Zn 2+ || Cu 2+ | Cu (s) When the salt bride or electrode is removed, or when having the same electrodes and salt solutions, the voltage remains to be 0. From the experiment, the conditions for which a galvanic cell is produced is when it has: – two but different electrodes – different electrolytes – a salt bridge which gave a voltage of 0.
The Term Paper on The Electrolysis Of Copper Sulphate Solution Using Copper Electrodes
Planning I did some preliminary work to see which current values, and for how long to time. The results of this are in the tables below: Electrode-1 AMass before (g) Mass after (g) Mass change (g) Anode 1. 381. 30-0. 08 Cathode 1. 351. 65+0. 30 This was done for 10 minutes. The mass lost at the anode should equal the mass gained at the cathode, which this doesn't, it has a percentage inaccuracy of ...
55. Evaluation: Without one electrode, there is no flow of electrons and the electrical circuit is incomplete. Both electrodes must be there to maintain electron flow, but electrodes must be different because it will not work if they were the same. One electrode must be more reactive than the other.
Without the salt bridge, there is no flow of ions, and there will be an imbalance of charges in the beakers, which is not possible. A salt bridge is needed to maintain neutrality. Sources of error include: – the electrodes could be rusted – contamination of substances – inaccurate readings on the voltmeter – having the electrodes on the wrong side, for eg. having the copper electrode as the anode and having the zinc electrode as the cathode. The experiment can be improved by: – using sand paper to remove rust on the electrodes – clean all equipment before using The reliability can be improved by: – comparing results with the rest of the class – repeating the experiment.
