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Vitamin C Practical Experiment Write Up

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Vitamin C Practical Experiment Hypothesis; Based on knowledge already at hand, My hypothesis will be that freshly squeezed juice will contain more vitamin C compared to juices that are from concentrate and that juice from lemons will contain more vitamin C due to their acidity. Variables; Variables such as temperature could affect the results that are collected, as much as can be done to control the temperature to make the results accurate will be done, holding samples with hands can increase the temperature slightly so they will be handled by the lip of the vial and placed into a rack. When testing samples multiple times I will ensure that the equipment cleaned and dried or if possible new as the pH of water might affect the reaction of DCPIP and ascorbic acid, water can also affect the results depending on whether it is 'hard water' or 'soft water', hard water contains more mineral and more chlorine is present. Measuring will be as close to as possible accurate, this will include re-measuring samples. I will be measuring the amount of juice sample solution it takes to decolourise 1cm of DCPIP, first I will use a controlled sample of 1% vitamin C to decolourise the DCPIP, and with this I can compare results from the other juice samples. ...read more.


to decolourise the DCPIP, 3 tests were conducted and from that you can then work out the average with a formula to get the average, the average can be used to conclude a fair result from all 3 of the trials. Vol. Of Juice Required to Decolourise 1cm(3) of 1% DCPIP Test 1 Test 2 Test 3 Average Vitamin C. Content Vitamin C Solution 6ml 7ml 9ml 7.3ml 0.13g Pure Orange Juice 14ml 15ml 18ml 15.6ml 0.06g Jiff 5.5ml 5ml 6ml 5.5ml 0.18g These results show that the juice sample that contains the most Vitamin C was the Jiff, with an average of 5.5ml to turn the DCPIP decolourised compared to the 15.6ml of pure orange Juice. The Vitamin C. Solution took 7.3ml to decolourise the DCPIP which was 1.8ml more than Jiff, This suggests to me that Jiff contains less water than the Vitamin C. 1% Solution did. With the average, I then calculated the Content of Vitamin C in each of the samples by Dividing them by the 1ml of 1% DCPIP Solution which gave the sum then converted to grams. These results prove my hypothesis in that freshly squeezed fruit will contain more vitamin C, this is because it will not have been watered down by manufacturers for a higher quantity. The results also prove my hypothesis is right that lemons contain more Vitamin C. ...read more.


The limitation of this experiment is that it was only repeated three times due to the amount of time available, more results would have given better accuracy in results and given me the chance to spot outliers in the experiment. We also do not know if Vitamin C is lost during ageing or through heat treatment which often products go through to ensure that it's free from harmful bacteria. One improvement that could be made to the experiment is the equipment, having a larger choice to use from, and enough so that other factors like water don't come into play. One modification that could used is that now we know that after a certain colour in the process of decolourisation we know that the trial is finished therefore saving us time for something else. Another Improvement is to be more careful with the juice samples and to keep them contained so that they are not affected by the elements. Summary; In this experiment, I learned that freshly squeezed orange juice will contain more vitamin C then juices from concentrate and that lemon contain more vitamin C then oranges. The experiment carried out was to measure the content of Vitamin C in the selected fruit samples, from the results I can conclude that the results were accurate, reliable and precise therefore allowing me to state this conclusion and to prove my hypothesis right! ?? ?? ?? ?? ...read more.

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