Electrolysis - How is the amount of copper deposited affected by the voltage?

Fair testing

To make this experiment fair I will; use the same amount of copper chloride (30ml) for each test, use the same graphite rods and sand them down to the same weight each time, do the experiment for the same length  of time (5 mins).

Apparatus

• Power pack
• 50ml beaker
• 2 wires (with crocodile clips)
• 2 graphite rods
• Plastic rod holder
• Sand paper
• Copper chloride
• Stop watch
• Filter paper (to filter and deposited copper in the solution)
• Funnel (to hold filter paper)
• Weighing scales (electronic for more accuracy)

Method

First I will plug in the power pack and the scales, pour 30ml of copper chloride into a beaker, sand a graphite rod, weigh it, record its weight and clip the negative wire to it (this rod is going to collect the copper because it is negative and the positive ions of the copper will be attracted to it), the other rod will have the positive wire clipped to it (this will attract the negative atoms of the chlorine gas and bubbles will be seen around the positive rod), both rods will be put into the holder and the holder will be put in the beaker. Now I will put the small wire on the power pack into 2v, turn on the power pack and start the stop watch. After 5 minutes I will turn off the power pack and stop the watch. I will unclip the negative wire from the graphite rod and put the rod on the scales. I have to filter the solution so that I can get the copper which has fallen to the bottom of the beaker. I will put what ever has been filtered with the rod on the scales and weigh it. I will record this and work out the amount of copper displaced by taking the starting weight and subtract it from the weight at the end of the test. Now I will sand the rod and weigh it to the same weight as before, tip the solution down the sink, pour another 30ml in the beaker, change the voltage to 4v and turn on the power pack and start the stop watch. When 5 minutes is up I will repeat he process of weighing, filtering, etc. I will repeat all of the process for each voltage on the power pack recording the results and working out the amount of copper displaced.

Results

Test 1

Test 2

Average results

Analysis

I think that the experiment was done fair apart from we couldn’t get the rod the same starting weight each time. My prediction was correct as the test with 12v displaced the most copper

Conclusion

I have found out that the voltage does affect the amount of copper displaced in that if you increase the voltage so do you increase the amount of copper displaced. If I did the experiment again I would try to get the starting weights the same and I would probably change the time instead of the voltage.