An investigation into the factors which affect the currentflowing during electrolysis

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An investigation into the factors which affect the current

flowing during electrolysis


Electric current is the flow of electrons. Sodium chloride in solution is able to conduct electricity because when dissolved sodium ions and chloride ions are produced. The chloride ions that are negatively charged due to their extra electron are attracted to the anode where they give up that extra electron and bond with other molecules to form the chlorine gas, Cl2. The extra electron then flows through the circuit to the cathode. H+ ions in the solution are attracted to the negative charge of the cathode and there they gain the extra electrons that originally belonged to the Cl- ions. Hydrogen gas is then formed and the circuit is complete.

2e + 2H+ → H2    2Cl- - 2e → Cl2


Concentration of NaCl- The bigger the concentration the more ions will be in the solution. This will mean that more ions will get to the electrodes, which means more electrons will get into the wire. This will greater the current.  

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Temperature- the ions will go quicker to the electrodes as the water will vibrate quicker when hotter. This will increase the current.

Voltage- The current would be decreased because by ohm's law v=ir

Surface area of the electrodes- if the surface area on the electrode increases there will be more space for the ions to go to and therefore the current will increase.

Out of these 5 variables I am going to investigate how the change in concentration can affect the current flow. I have chosen this one because I think that it is the most reliable and I ...

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#3# The spelling and grammar are good. The scientific language used was relevant and well placed, the only thing that could be done to improve this area is that the terms used to be explained to show an even deeper understanding of the subject

#2# The explanation used in the first section of this essay shows that the student has a good understanding of electrolysis an how electricity flows, because they can transfer it to their ideas and predictions. It is a higher level skill if you can make links between different topics to come up with a explanation behind your theory. The way in which each of the experiments were carried out to come up with the final design was good, but more explanation could had been give as to why it was bad that the results were too low, was it was because the error would be to high in them or was it because it was had to determine a pattern between them?

#1# The student has obviously thought very hard about how this experiment was going to be carried out. The response is very explicit as to how the experiment was carried out and how the final designed was determined but there was very little on the evaluation and interpretation of the final results. When conducting an experiment the interpretation is possibly more important than the experiment its self.