Does the Magnitude of current affect the rate of electrolysis?

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Nathan Hart                

Science Coursework

Does the Magnitude of current affect the rate of electrolysis?

Plan

The circuit that I shall use in this experiment will be built as the diagram shows.

During electrolysis the copper electrodes either receive from or donate to copper ions from the copper sulphate electrolyte solution. If the electrolysis is affected by the magnitude of the current flowing then by measuring the current an  

With the power on I shall adjust the variable resistor to give the exact current flow required (I can do this by observing the ammeter reading). The current flows that I will need (on different experiments) are:

  • 0.10A
  • 0.15A
  • 0.20A
  • 0.25A
  • 0.30A

The circuit will then be left for ten minutes (on every test). Before and after every experiment the electrodes will be weighed. The weighing of electrodes allows us to:

a) See if electrolysis has taken place.

b) Measure the rate of electrolysis in Copper Sulphate and therefore we will be able to deduce whether a higher current affects the rate of electrolysis.

We know when electrolysis has taken place because the negative electrode (cathode) will have increased in weight, the weight of the positive electrode (anode) having an inversely proportional result. If my results are immaculate I will find that the weight gained on the cathode will be equal to the amount lost on the anode e.g. +4, -4.

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Why is this?

From my scientific knowledge I know that, in the electrolysis of a solution; the positive ions will be attracted to the cathode (Cations), and the negative to the anode (Anions). These two events happen at the same rate. Gradually, with the transfer of electrons, the anode is reduced in weight (and mass), the cathode on the other hand, increases in weight (and mass).

Safety

To keep my experiment safe I shall:

  1. Conduct the test standing at all times.
  2. Only alter the circuit when the power is off at the mains.
  3. ...

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