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We can see clearly from these graphs that as the concentration increases so does the rate of reaction.
From the relatively straight lines of best fit we can tell that the rate of reaction is continuous with each different concentration. Scientific Model: From these results we can tell that as the concentration of H2SO4; when increased in the solution of 20ml H2SO4 and H20 (Sulphuric acid and water -a neutral chemical in this experiment-) the higher the rate of impact between H2SO4 and Mg; and so higher the rate of reaction.
Proving the prediction on the basis that the higher the concentration of a reactant is the higher the rate of reaction (Increase in H2SO4 concentration = Increase in the rate of reaction), by literally increasing the ratio of the reactant substance the rate of reaction is increased dramatically and the faster the products are released.
Test of scientific model: The proof of this scientific model is seen in the way that the lines of best fit are straight showing that the concentration of a reactant is equally relational to the rate of reaction.
We can also prove this by seeing that the higher the concentration of H2SO4 the higher the overall rate of reaction is (see the mean average graph). This shows us that the scientific model is accurate. Evaluations: The results from my experiment were a relative success, although there were some major anomalies, the individual concentration graphs and the mean average graph gave me enough information to come to some sort of a conclusion on whether my chosen factor has a bearing on the rate of reaction of magnesium and sulphuric acid to produce Epsom salts.
The evidence I can give this can prove my prediction and the scientific model.
On the whole the experiment was a success and mostly encountered anomalies that although quite large are not on such a large scale to stop me from reaching a good accurate conclusion. The worst anomaly in the whole experiment was on the 40% concentration experiment, although this anomaly can only be seen to its full extent in its individual graph: The large difference between Run-3 and the other runs is vast, this is lightly to be the result of human error like many of the other anomalies, most lightly reason being that the concentration of H2SO4 or the mass of Mg used in that run.
This highlights that there is problems with the procedure and the accuracy of me and my groups experiment. The anomalies that are present in the experiment are overall minor but the reasons for there occurrence are relatively small in most cases apart from the result shown in run-3 of the 40% test. The main reasons can be split up into two main categories, procedure failure and equipment failure. I will not highlight the main problems: Procedure failure: 1.
Considering that the levels of hydrogen being released where measured by eye via the measuring cylinder, leaving huge space for human error, there could have been some serious cases of misjudgment. This would make the results and the graphs slightly inaccurate. 2. The results may have been written or copied down inaccurately, giving a false set, resulting from minor to severe anomalies. 3. The magnesium may and lightly to of been weighted incorrectly, creating a higher or lower rate of reaction compared to the amount being tested. (this could have been the cause of the large anomalous results in the 40% concentration test)
4. The sulphuric acid was measured out in a rush and some confusion could have been caused and the wrong ration of H2SO4 and H20 may have been put into the measuring cylinder, resulting in anomalies. 5. The measurement of hydrogen might not have been accurate to the time intervals. 6. The measuring cylinder may not have been completely full of water, creating an overall inaccurate run. Equipment Failure: 1. There may have been a very small leak or an opening in stopper or in the side arm tubing, this would cause the results to be inaccurate.
2. The electronic scales may have been giving false measurements but this could also be due to human error or recording of the measurements given by the scales. 3. For the lower concentration (lower rate of reaction) runs. The large measuring cylinder used for collecting the results, may have been to large to get an accurate reading because of such small increases in hydrogen volume, it may have been wiser to use a smaller measuring cylinder for the lower concentrations, but this was only to be discovered after the experiment was completed.
Extended investigation: Research: There are a number of ways that I could extend and improve this investigation, the one bellow should generate considerably more accurate results and cut down on the floors in procedure and equipment failure in the tests. This involves removing the large measuring cylinder, and the tub of water and replacing it with a ‘gas syringe’. This piece of equipment is made for measuring volumes of gas and so is perfect for such an experiment where we are measuring the amount of gas given off by a reaction.
Diagram: The advantages for using this piece of equipment are: 1. The measurements are more accurate and than guesswork by eye. 2. Likely hood of it leakage or incorrect reading reduced. 3. Less equipment is used. (taking away the measuring cylinder with and the tub of water) I would also change the measurements of the chemicals to be moles so we can get accurate calculations and so we can tell if the experiment ran accurately by the amount of produce Hydrogen and MgSO4 are left at the end of the experiment.
Revised Method and apparatus list: Apparatus: Goggles Method: Set up apparatus as before BUT instead of preparing water with the upturned measuring cylinder, attach the gas syringe to the clamp stand and secure the end of the side arms delivery tube to it. Then continue the procedure as normal recording the results from the readings on the side of the gas syringe.
Diagram: Conclusion: The experiment went well, at the end of the experiment, i am able to conclude that from the results given from the practical and from the research taken that my prediction is accurate. As the concentration of H2SO4 is increased so does the rate of reaction equally until either of the reactants are used up to the point that the concentration (of sulphuric acid) or the surface area (of the Magnisium because of the lack of molecules after most of them have reacted) .
The conclusion states the facts originally shown in the prediction and those backed up in the observations in the scientific model after the experiment. The anomalies that occurred did not have any crucial bearing on the experiment as it does not require accuracy to a finite level as long as the results are moderately accurate I can come to a conclusion. 1 Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.