Electrolysis Investigation

Authors Avatar

Planning Experimental Procedure

Affecting Factors – A list off all the possible factors, which would affect the resistance of a cell.

  • Exposed Area of Electrodes – An electrode with a larger exposed (to the solution) surface area would mean, the electrodes would not limit that rate of electrolysis. The larger the surface is, the higher the rate of electrolysis, due to there being a larger amount of copper, which can ionise. The surface are of the electrodes should be maintained the same.
  • Purity of Electrodes – The higher the purity of the electrodes, the lower the resistance. This is because there are n other elements which could get in the way, and therefore increase the resistance of the solution.
  • Voltage – In all cases, increasing the voltage will decrease the resistance. In this case, the greater the voltage, the greater charge on the electrodes and so the greater the attraction for ions. This will be investigated in our preliminary tests.
  • Current – Based on past knowledge, increasing the current also increases the resistance, due to the build up of heat in the wire.
  • Concentration of Solution – The higher the concentration of the solution, the lower the resistance will be. A strong concentration which is made entirely of Copper Sulphate will be a lot better for electrolysis than a diluted solution, because the ions are able to move more freely.
  • Distance between electrodes – The further the distance between the electrodes, the further the ions have to travel, which would mean an increase in the resistance. The distance, which we place them apart, will be decided by to factors. a) If they are to close, the may touch and short circuit and b) The size of the beaker which we do the experiment in. The distance will need to be kept constant to ensure that it is a fair test.
  • Temperature – The higher the temperature the greater the resistance because there would be more energy in the solution, making it more difficult for the ions to move. A high current could cause the solution temperature to rise, and so it is important that the temperature be kept approximately the same.

Explanation – A scientific explanation of electrolysis an resistance.

Electrolysis is the process of decomposition by electrical action. Elements are produced at each electrode. In this case, we are using copper sulphate solution. When the solution is being electrolysed it starts to decompose. Ions are created which are the moving particles in solution. CATions travel to the CAThode. ANions travel to the ANode. Anions being negatively charged deposit electrons on the anode. Cations being positively charged pick up electrons from the cathode. Other electrons move around the circuit (from the anode) to replace them. In the circuit, electrons flow, just as if the circuit was made of conducting wires. This is how the solution conducts electricity.

Join now!

Copper ions are formed at the cathode:

Cu2+ + 2e- Cu

The anode decomposes forming copper ions:

Cu Cu2+ - 2e-

The result is that the anode wears away while cathode gains mass. When the copper anode decomposes it loses two positively charged copper ions and electrons. Copper ions then move toward the cathode, which has a negative charge. At the cathode, the copper ions each receive 2 electrons and become copper atoms:

Cu2+ + 2e- Cu

The copper atoms collect together on the cathode, which results in it gaining mass. The hydroxide ions in the solution decompose and are ...

This is a preview of the whole essay