Monday, 20 May 2013

Electrolysis - electrode mass vs current

Equipment

Power supply
Rheostat
Ammeter
Electrode holder
Carbon electrodes
Copper sulphate solution
Beaker
Stopclock
Top pan balance


Method

Add 150 ml of the copper sulphate solution to the beaker.
Connect the electrodes to the power supply via the rheostat and ammeter in a series circuit.
Weigh the negative electrode on the balance.
Add the electrodes to the solution and set the rheostat to minimise the current.
Start the stopclock and switch on the power, noting the current.
After 5 minutes switch off the power, remove the negative electrode and rinse using the water.
Dry the electrode and weigh it again.
Empty and resupply the beaker with the same volume of fresh solution.
Adjust the rheostat, replace the electrode and repeat the process.

Aim to get at least five different readings of mass gained for different currents.
If you have time repeat the entire experiment 3 more times

Plot a graph of the mass gained vs current.

Note - Copper Sulphate is toxic, care should be taken when handling it and hands should be washed after the experiment.