Lab12_Analysis of Vitamin C in Food.pdf

Value of 250 mg of vc refers to the

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value of 250 mg of vc refers to the advertised/reported amount of vc that is supposedly present in the tablet. Percent error of the estimated values can be calculated relative to the actual sum and the reported value of the vc content. In addition, we can calculate the percent error of our sum of the vc contents per halves relative to the reported value this would mean that we would be under the assumption that the label is entirely correct in claiming that the tablet has exactly 250 mg of vc. These percent errors are shown below in the aforementioned order. ?. ?. ??1 = |223?? − 228??| 228?? × 100% = 2.19% ????? ?. ?. ??2 = |232?? − 228??| 228?? × 100% = 1.75% ????? ?. ?. ??1,250 = |223?? − 250??| 250?? × 100% = 10.8% ????? ?. ?. ??2,250 = |232?? − 250??| 250?? × 100% = 7.20% ????? ?. ?. ??? = |228?? − 250??| 250?? × 100% = 8.80% ????? The calculations for the vc content of the orange juice (O 1 ), boiled orange juice (O 2 ), and Country Time Lemonade Drink Mix (C) were done in the same manner as for the vitamin c tablets. We are unable to calculate percent error as the actual content for these substances was not given/we did not record the values given by the labels assuming they were given at all. Therefore, the table below simply shows the calculated values of the number of moles of vc and the mass of vc.
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Table 3: Calculated vc content for oj and ct (mol) (mg) (mg/mL) Trial n KIO3 n vc m m/V O 1 0.0219 0.0657 11.6 0.231 O 2 0.0229 0.0687 12.1 0.228 (mg vc/g ct) C 0.0083 0.0249 4.4 0.438100699 ?????𝑎?? ?? 𝑣? ??????? ?? ?? = 0.228 − 0.231 0.231 × 100% = 1.30% ?????𝑎?? Discussion 1. Overall balanced equation of the titration 3? 6 ? 8 ? 6 + ?? 3 → 3? 6 ? 6 ? 6 + ? + 3? 2 ? 2. There are 6 electrons involved in this redox reaction: per the formula above 3. Vitamin C would be expected to react with oxygen under acidic conditions as it would pull the hydrogen atoms from the vitamin c to form water. 4. Pasteurization of orange juice may not have implications on vitamin c content. In this experiment, the orange juice was boiled, and as a result, there was a 1.30% drop in vitamin c content. However, there are multiple things to consider. Pasteurization does not involve boiling, it simply requires the orange juice to reach a particular temperature and that temperature is maintained for a designated amount of time and the oj is then cooled. Thus, similar results or even lower reductions in vitamin c could be expected. At the same time, the low percent decrease that resulted may have simply been a result of the evaporation of water and thus increase in concentration of vitamin c of the oj. Though, this may be negligible. 5. PubMed is a reliable source ( ) and this article claims that vitamin c may help to prevent diseases such as cancer as a result of its role as an antioxidant. It prevents oxidation in our bodies as it is more easily oxidized and thus will be oxidized before any important molecules / cellular structures are affected by oxidization in the human body.
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  • Spring '14
  • Chemistry, Orange Juice, color change, Lemonade Drink Mix, Time Lemonade Drink

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