• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Vitamin C Lab

Extracts from this document...

Introduction

Stephanie Chan 12HT Biology HL - Mr. Etheridge Vitamin C Investigation Introduction Ascorbic acid, commonly known as Vitamin C, is a water soluble, essential vitamin for the body (meaning that it has to be acquired from our diet). It has the molecular formula of C6H8O6 and the structural formula can be seen on the right. Vitamin C is vital for the formation of collagen, a main component of connective tissues and the basis for the general shape and structure of the body. Vitamin C not only serves as an integral part of maintaining the function of blood vessels, bones, teeth and many other various connective tissues, it is also an antioxidant. This function allows the Vitamin C to protect the body from other water soluble molecules that could create free radicals (atoms which may cause damage and mutation to cells) when oxidised. Furthermore, it has also been shown in research that Vitamin C stimulates the immune system, and coupled the antioxidant function, it may help prevent and treat infections and diseases (generally used to combat the common cold). Because Vitamin C is a strong reducing agent - hence its function as a good antioxidant - it can also be easily changed by oxidising agents. This is particularly evident when Vitamin C is exposed to atmospheric oxygen, the concentration will be reduced due to the ascorbic acid oxidising with the surrounding air, and in addition, ascorbic acid is also sensitive to light. ...read more.

Middle

Vitamin C And from one titration, 2.10cm3 DCPIP decolourises 2.00cm3 of Vitamin C, To calculate concentration of Vitamin C, the amount of DCPIP must equal to 2cm3 for the data to be quantifiable and equivalent to the standard, hence In order for the 2.10cm3 DCPIP to equal to 2.00cm3, it must be multiplied by (2/2.10) cm3 DCPIP = 0.95 And to keep the ratio of 2.00cm3 of 1% DCPIP decolourises 4.00mg of 0.1% Vitamin C the same, Lemon Juice = 0.95 � 2.00cm3 = 1.90 cm3 Hence, 1.90cm3 of lemon juice contains 4mg is required to decolourise 2cm3 of DCPIP, 4.00mg Vitamin C/1.90cm3 lemon juice = 2.10mg Vitamin C/1 cm3 Lemon Juice Because 1mg of Vitamin C is in 1cm3 of solution, or 0.1%, Therefore the concentration of 1.05mg/cm3 Vitamin C in 1cm3 lemon juice is = (2.10 � 0.1%) � 100 = 0.210% Uncertainties Pipette uncertainties: The pipette used in this experiment measures 2.00cm3 of lemon juice � 0.04cm3. The uncertainty due to the pipette is thus (0.04/2) � 100 = 2% Burette uncertainties: Lemon Juice at 10�C Uncertainty (cm3) / Measurements (cm3) � 100 Uncertainty Percentage (%) �0.1 20.7 0.48 22.3 0.45 Overall uncertainty (%) + 2 (uncertainty of the pipette) 2.93 Lemon Juice at 25�C Uncertainty (cm3) ...read more.

Conclusion

This mistake could lead to a great unreliability in our data (particularly the titrations done in the latter parts of the entire experiment) due to the addition of oxidised Vitamin C from being exposed to the air. Another aspect we could have improved upon was the amount of time each test tube of lemon juice spent inside the water bath, as the decomposition of the concentration of Vitamin C can vary depending on how long it has been heated for. Another problem with our method regarding the heating of the lemon juice was that the temperature of our lemon juice was not constant, particularly when we placed the lemon juice in the 80�C water bath and waited for the temperature to drop to 55�C. This method an unreliable way to see how 55�C would affect Vitamin C because the oxidation rate would have been different at 80�C than it would have been if the temperature had stayed at 55�C. In addition, a possible further experiment could be done to see the relationship between Vitamin C concentrations in a solution to the different amounts of time of heating it at a constant temperature (not at room temperature). Another way to make this experiment easier to calculate the results is to filter the lemon juice through filter paper so we could titrate the lemon juice in a burette like we normally have in previous determining Vitamin C concentration experiments. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Biology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Biology essays

  1. Vitamin C concentration

    that among solutions used it has the highest concentration of vitamin C (0.1%). Second highest vitamin C concentration has Rutinoscorbin and new lemon -0.057%. The lowest vitamin C concentration has tomato juice from carton- 0.009%. To put those results from the highest to the lowest vitamin C concentration: I.

  2. COMPARATIVE INVESTIGATION LAB ON LICHENS

    15.70 Comparison of the two raw data by using the t-test method which will determine whether the percentage coverage of lichen on trees in sunny areas and on trees in shady areas have a significant difference. Null Hypothesis: there is no significant difference between the percentage cover of lichen on

  1. Biology- Extended essay. For this research, I investigated the effects of DDT and ...

    The fish food was bought by from the same local fishery thus providing equal nutrients to all the fishes. (Crude Protein: 32%, Crude Fat: 45, Crude Fiber: 55, moisture: 10%) - As per the proximate analysis provided behind the cover of the food.

  2. Penicillin - its discovery, properties and uses.

    Fleming found that if he took a sample of mucus and spread it over a petri dish treated with penicillin, then he could grow a pure sample of Pfeiffer's bacterium, because it was immune to penicillin, while the bacteria that normally overwhelmed it were sensitive to it.

  1. Molecular Genetics: differentiating between various molecular databases

    in 86 aa overlap Number of similar AA pairs (:) 55 % of total 55/110 = 50% Number of conservative AA pairs (.) 13 % of total 13/110 = 11.8% Number of different AA ( ) 42 % of total 42/110 = 38.2% Table 2: Comparing Crested Porcupine and Hamster Species Crested Porcupine (Hystrix Cristata)

  2. The Effect of Temperature on the Vitamin C Content of Lemon Juice

    There is some discrepancy with the error bar for my ‘60°C’ result with gave it a larger standard deviation of 3.7 opposed to the other results which had standard deviations of 0.42-1.1, this could have been caused by some systematic errors which I will explore in my evaluation.

  1. How does cooking affect the amount of vitamin C in lemon juice?

    DATA COLLECTION AND PROCESSING 1. Data Collection 1. Qualitative Data 1. Glacial acetic acid is a colourless solution. It releases pungent and choking smell. 2. Lime juice is a yellowish solution and releases tangy smell. 3. DCPIP is a dark blue solution. When lime juice is titrated into DCPIP, the DCPIP gradually changes from dark blue to pink and eventually decolourises.

  2. Effect of Incandescent, Fluorescent and LED lights at 900 lumens on the concentration of ...

    is applied into titration burette and final volume when the right amount of ascorbic acid solution is titrated into 0.01M of DCPIP. Controlled Variables: Controlled Variable How is it being controlled Why is it controlled The quantity of light emitted: Incandescent, led, and fluorescent light bulbs will emit 900 lumens of light.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work