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Electrolysis is a powerful technique used to break down a substance by electricity. Electrolysis only occurs when an ionic substance is molten or is in a solution. This liquid substance is called an electrolyte.

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Introduction

BACKGROUND:- Electrolysis is a powerful technique used to break down a substance by electricity. Electrolysis only occurs when an ionic substance is molten or is in a solution. This liquid substance is called an electrolyte. Electrolytes are made up of ions. They are molten or in a solution so that the ions are free to move. The ions present are attracted to the electrode with the opposite charge: * Positive ions are attracted to the cathode (negative electrode). * Negative ions are attracted to the anode (positive electrode). As this is happening, a redox reaction is taking place. A redox reaction is when oxidation and reduction happen simultaneously. When a substance is oxidised it loses electrons, when a substance is reduced it gains electrons. * At the anode, the negative ions lose electrons and are oxidised. * At the cathode, the positive ions gain electrons and are reduced. In the experiment, sulphuric acid was added to the water to form an acidic solution because pure water is unable to conduct electricity. This is because the charges are balanced. Sulphuric acid (H2SO4) forms ions in water: H2SO4 (aq) � 2H+ (aq) + SO42- (aq) In the dilute solution there are these atoms present: H+ and SO42- from sulphuric acid, H+ and OH- from water CIRCUIT DIAGRAM:- AIM:- The aim of the experiment is to investigate factors which affect the size of the current which flows through during electrolysis. ...read more.

Middle

As the depth of the electrode in the dilute acid increases, so will the amount of hydrogen and oxygen liberated because the current will be going up. RESULTS:- * Investigating the affect of varying the distance between electrodes: Distance (mm) Current (Amps) Current (Amps) Average (Amps) 15 0.28 0.29 0.29 30 0.23 0.23 0.23 45 0.20 0.20 0.20 60 0.18 0.18 0.18 75 0.16 0.16 0.16 * Investigating the affect of varying the depth of the electrode in dilute acid: Depth (mm) Current (Amps) Current (Amps) Average (Amps) 10 0.27 0.25 0.26 20 0.36 0.33 0.35 30 0.43 0.41 0.42 40 0.48 0.46 0.47 50 0.49 0.52 0.51 60 0.57 0.58 0.58 ANALYSIS OF RESULTS:- Distance Between Electrodes From looking at the graph produced from these results, I can conclude that as the distance between the electrodes increase, the current flow decreases. I think that this is because of an increase in resistance as the electrodes are moved further apart. These results support my prediction because as the distance between the electrodes increases, the flow of current decreases. This is because the further apart that the electrodes are moved, the more resistance is formed making it more difficult for current to flow. ...read more.

Conclusion

The results that I received followed my prediction. There is no doubt from my results that as the distance between the electrodes increases, the current flow decreases. Also, as the depth of the electrode submerged in the dilute acid increases, so does the current flow. In order to improve the accuracy of my experiments there are various things that I could do. When carrying out the electrode depth experiment, I would use a clamp when submerging the electrodes to ensure that the electrodes were held still in the dilute acid. This would ensure that the electrodes were held at the exact correct depth when reading the ammeter. It would also ensure that the electrodes were held the exact same distance apart as from the first experiment, one can see that this is another factor that affects current flow. I also think that by extending the ranges for both of the experiments, i.e. extending distance between electrodes to 100mm the extending the submerged depth of the electrodes to 100mm, this would ensure that a wide enough range was covered to be sure about the shape of the graph as I would get a lot more readings. This could also be used to determine whether or not the graphs will eventually level off. Zilia D'Mello Page 1 Chemistry Coursework Mr Hermes Electrolysis Assessment ...read more.

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