An Investigation Into What Affects How Much Copper Is Deposited On A Pure Copper Cathode.

We choose to change the amount of current passed through the electrodes using a variable resistor. I choose this because it is simple and gives off good and clear results.

Predictions

A simple prediction would be to say that the mass of copper deposited at the anode would decrease, and the mass of copper deposited at the cathode would increase. It is also possible to predict when using time as a variable, that the relationship between the time the current flows and the mass of copper deposited at the cathode will be proportional. I can then predict that if I double the time of the experiment, I will be doubling the charge. I know this by doing research, and this prediction can be supported by Faradays law (you can see this under Faradays law).                                                                                    Faradays Law

Michael Faraday said that;

“The mass of any element deposited during electrolysis is directly proportional to the number of coulombs of electricity passed”.

96500 coulombs deposited 1 mole of a metal with a single charge on its ion, e.g. na+.

Method

• Scrub copper electrodes, rinse in water and dry them through out the experiment.
• Weigh and record anode and cathode
• Get 75ml of copper sulphate
• Put into a circuit with a power pack, an ammeter and a variable resistor, using crocodile clips, but make sure the copper isn’t touching.
• Turn power pack on (7 volts)
• Time for 3 minutes
• Remove the copper and dry it, weigh it and record the results

Results

All experiments are timed for three minutes and are on seven volts.

Experiment:

1.

2.

3.

Conclusion

My results have supported my prediction, as you can see the amount of copper deposited on the cathode increases and decreases on the anode (to see this refer back to the results).

Evaluation

The experiment may have been successful but improvements could have been made. If I was to make it more successful I would use new copper, as other people had used them in previous lessons. I would make sure the copper was completely dry before recording the results. As we were doing the experiments from lesson to lesson the sulphate solution could have changed between lessons and I would also use the same equipment and electrodes. But if I was to do the experiment again I would leave the solution for a longer time before getting results.

I enjoyed doing the experiments and I would like to do it again but by using different variables.