chemy final presentaion stpm

8/13/2019 Chemy FInal Presentaion STPM

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TITLETo determine thepercentages of vitamins C in

various type of BRANDS OFORANGE JUICES


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Abstracts

The title of this project is to determine the

percentages of vitamins C in various brands orange

juices. This is not just to ensure consumers are able

to have a healthier and safer lifestyle, but alsoallowing them to have a better understanding about

orange juices on the market

we have used the 2,6-dichlorophenolindophenol, (

DCPIP, also DPIP ) titration method. This method

requires us to measure amount of volume of various

brands of vitamin C needed to decolorize the DCPIP

solution


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Introduction and Background


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Importance of Vitamin C

Amount of vitamin C in different brands of

orange juice

Objectives


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Most important nutrient

may not be the cure for common cold

protection against immune systemdeficiencies, cardiovascular disease, prenatal

health problem, eye disease and even skin

wrinkling.

500 miligrams daily to achieve health

Vitamin C


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Process of preparation of ready-make orange

juice

Sunkist,Tesco Choice, Minutes Maid,

Tropicana Twister.

Amount of vitamin C in different

brands


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Methodology

1. Hypothesis

2. Method3. Variables

4. Apparatus

5. Materials6. Procedure

7. Results

DEFINITION: A system of methods used in a

particular area of study. In This Case, study

about howtopicresults


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Hypothesis & Method

Sunkist, brand of orange juice

contains the highest amount

of vitamin C percentage.

Quantitative Analysis.

Student during titration with a burette


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Variables

Constant Variables: Amount of 0.1% DCPIP solution used.

Manipulated Variables: Brands of orange juices.

Reponding Variables: Percentage of vitamin C among brands oforange juices.

Brands of orange juices

0.1% DCPIP Solution

Vitamin C %

Black Guy With An Oranges Facts


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Apparatus & Materials

Test Tubes

x5

Syringes x 6

Beakers x2


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0.1% ascorbic acid (vitamin C)solution (standard solution)

50ml

0.1% freshly prepared DCPIP solution (0.1 gDCPIP in 100ml distilled water)100ml

Minute Maid Tropicana Twister Sunkist

Peel Fresh

Tesco Choice


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ProcedureS

Use 1 ml-syringe to add 1.0 ml of 0.1% DCPIP in test tube.

Draw up 5.0 ml of 0.1% ascorbic acid solution into a 5 ml-syringe, and expel any air bubbles.

Place the needle end of the 5 ml syringe in the 0.1% DCPIP and add one drop of the 0.1% ascorbicacid solution to the DCPIP in the test tube. Shake the test tube gently to mix it.

Repeat step 3 until the mixture in the tube has decolorized

Record the volume of ascorbic acid used to decolourised the DCPIP.

Repeat steps (1)(5) for two times. Then calculate the average volume used.

Repeat steps (1)(4) on a range of different brand of fruit juices using 1ml of DCPIP each time. The percentage of vitamin C in each juice sample is calculated as follows:

One molecule of ascorbic acid reacts with one molecule of DCPIP, changing its colour from blue tocolourless.

Let the volume of 0.1% ascorbic acid solution that decolourise 1 ml of 0.1% DCPIP solution = X ml

Let the volume of brand of fruit juice extract that decolourise 1ml of 0.1% DCPIP solution = Y ml.

Therefore the quantity of ascorbic acid present in the Y ml of juice extract equals the quantity of

ascorbic acid present in the X ml of the 0.1% ascorbic acid solution. Therefore, the concentration of ascorbic acid in juice extract = ( ) x 0.1%

Result:


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Results

Result:


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Observations

1 2 3

4 5 FINAL


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Discussion [Problems & Solution]

1) Mixing the flask is important to ensure that the solutions have co mpletely reacted with each other. Whenadding the iodine solution, you may see a temporary color change that goes away when you swirlthe flask. The color change that is important for this experiment is the one that is not temporaryand does not go away after mixing the solutions.

2) There are a number of reasons your titration may not work. Three of the most commonproblems that can lead to a solution not changing colors in a titration are:

Using the wrong substances. Make sure that you use Lugol's DCPIP solution or anotheriodine solution sold as a DCPIP indicator (not a pure potassium iodine solution) and a true, solubleDCPIP. (If you purchased the Science uddies kit, this problem would not apply. The materials in the kitare correct for this Project Idea.) Comparing DCPIP Solution

Using incorrect concentrations. If your vitamin C standard solution is too concentrated or your DCPIP titrationsolution is too dilute, or your DCPIP indicator solution is not between 0.5 to 1.0%, it may requiremuch more than 50 mL of DCPIP solution to titrate the standard solution and/or orange juice. Themost common problem here is an overly dilute DCPIP solution; sometimes, the Lugol's DCPIP solutionsold in stores is already dilute, and you don't need to dilute it more.

Using too much orange juice. If there is a large amount of vitamin C in the orange juice that is beingtested, it may require more than 50 mL of DCPIP titration solution for it to change color. You couldtry using a smaller volume of orange juice.


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Conclusion

Different brands of orange juices have

different amount of vitamin C content or

percentages. Sunkist, brand of orange juice

contains the highest amount of vitamin Cpercentage among other brands of orange

juices.

chemy final presentaion stpm

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