What affects the rate?
Electrolysis uses the flow of electrons to attract positive metal ions to the cathode (-) and negative non-metal ions to the anode (+). Therefore the more charge that has passed, the more metal will be deposited on the cathode. If you leave the current on or increase the current then you get charge and get more metal deposited.
What is happening?
In the experiment I am doing I will use copper sulphate solution- Cu2+SO42-
The Anode is positively charged so attracts the SO42- and takes excess electrons. It also attracts OH-. 4OH- makes O2+2H2O+4e- (4 negative electrons). The Anode is made of copper so the copper looses electrons and becomes positively charged. These copper ions then move to the cathode.
The Cathode is negatively charged so attracts copper ions. The copper ions gain electrons and become copper atoms.
For this experiment I will need:
two copper electrodes
a power pack
some copper sulphate solution
two crocodile clips.
I will set them up like this:
To make it a fair test I will use the same beaker, the same concentration of copper sulphate, the same amount of solution and the same voltage and not put the crocodile clips in the solution.
I am changing the time that the electrodes are in the solution. I will test to see what voltage to use and what times are sensible.
I have decided to use 4V from 1 to 5 minutes.
I predict that
Here are the results I gathered: