Sunday, 2 June 2013

Electrolysis - purification of a sample


Impure samples of a metal can be purified by using the method described below. This method is for purifying a copper sample, but by substituting a different metal and a solution of one of its salts you will achieve the same results.

Place the sample of copper to be purified onto the positive terminal and a piece of the pure copper metal onto the negative terminal.

Both electrodes should be placed into a solution of a salt of the copper, copper sulphate is ideal for this purpose, though care should be taken as it is toxic. It is important that the two electrodes do not touch.

The copper from the impure electrode will be taken into solution and copper from the solution will be deposited on top of the pure copper electrode.

You may wish to weigh the electrodes (dry) before and after this experiment and compare the mass lost by one to the mass gained by the other.