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Does the Magnitude of current affect the rate of electrolysis?

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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 infrom the copper sulphate electrolyte solution. If the electrolysis is affected by the magnitude of the current flowing this could be demonstrateden by measuring the current and weighing the electrodes before and after a fixed period of time. The positive ions of copper in solution will deposit at the negative cathode which will therefore gain in weight whilst the positive anode will release copper ions into the electrolyte and so lose weight. Method With the power on I shall adjust the variable resistor to give the exact current flow required (I can do this by observing and recording the ammeter reading). The current flows that I will need set in(on different experiments) are: * 0.10A * 0.15A * 0.20A * 0.25A * 0.30A The circuit will then be left for a measured ten minutes (on every test)at each current setting. Before and after every experiment both the electrodes will be weighed. The weighing of electrodes allows us to: a) See Confirm whetherif 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. ...read more.


* If current had nothing to do with the rate of electrolysis, there would not be power plants situated next to every place where this process is carried out industrially. * Increasing the current requires more ions in solution to deposit their charge at the electrodes. The more ions reaching the electrode the more copper is deposited/released * As the weight gain/loss at the electrodes should be proportional then the weight deposited per unit current should be a constant Results The results of the average weight gains/losses at electrodes for each experiment have been recorded in Table 1. The average weight gain/loss (g) for each current level has been calculated. The average weight change per unit current has also been calculated (mg/amp) Table 1 Average weight gain/loss at electrodes + - + - + Amps (A) WEIGHT (g) Mg/amp-0.03 +0.05 -0.06 +0.04 -0.05 Electrode +/- Before After DifferenceAfter Average changeDifference +0.01 -0.01 +0.04 -0.04 +0.04 - 0.10 0.84 0.85 +0.010.85 0.01 100 + 0.10 0.88 0.87 -0.010.87 - 0.10 0.850.62 0.86 +0.01 + 0.10 0.870.62 0.86 -0.010.58 - 0.15 0.620.87 0.66 +0.040.91 0.04 267 + 0.15 0.620.85 0.58 -0.040.82 - 0.15 0.661.12 0.70 +0.031.17 + 0.15 0.580.98 0.54 -0.050.92 - 0.20 0.870.94 0.91 +0.040.98 0.035 175 + 0.20 0.850.75 0.82 -0.030.70 - 0.20 0.91 0.94 +0.03 + 0.20 0.82 0.78 -0.04 - 0.25 1.12 1.17 +0.05 0.055 220 + 0.25 0.98 0.92 -0.06 - 0.25 1.17 1.23 +0.06 + 0.25 0.92 0.87 -0.05 ...read more.


* Not drying the electrodes properly (increased weight - water) * The balance did not have sufficient accuracy for the measured weight range Possible alterations The experiments could be further improved and standardised to remove variables and improve accuracy as follows: 1. The experiments could be repeated more times, and therefore gaining a higher degree of accuracy in the average weight gain/loss. . 2. Instruments and balances of greater accuracy could be used 3. By introducing an evaporation drying process we could remove a major variable of level of drying the electrodes. I consider this the possibly greatest variable in the experiment 4. By using a constant area and weight electrodes set at constant separation which would create the same conditions at each electrode between experiments. These would change during electrolysis and if different to start with could possibly affect the accuracy of measurements when comparing one experiment with another. 5. Using a fresh amount of electrolyte for each experiment would ensure the same starting conditions in solution Viewpoints of my experiment I could also: * Test this experiment using other solutions and electrode materials. * Test for the effects of a voltage increase. * Run this same experiment over a split longer period of time, (weighing each electrode in each interval, before continuing the test. )This would show if the electrolysis rate would remains constant throughout the electrolysis period. * Repeat the tests at higher temperature of electrolyte Nathan Hart Science Coursework Page 1 of 5 07 May 2007 ...read more.

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