Quantitative Analysis of Vitamin C Contained in Ribena

Topics: Ascorbic acid, Vitamin, Vitamin C Pages: 3 (650 words) Published: April 11, 2011
Title: Quantitative analysis of vitamin C contained in ribena

Aim: to determine the amount of Vitamin C in a sample of ribena Materials:
* Vitamin C (ascorbic acid, C6H8O6)
* 4% potassium iodide (KI)
* 1M acetic acid (CH3COOH)
* N-bromosuccinimide (NBS, C4H4BrNO2)
Apparatus:
* Conical flask
* 100 ml volumetric flask
* Weighing bottle
* Analytical weight balance
* Spatula
* Funnel
Results:
Item:| Mass in grams|
Mass of weighing bottle with ascorbic acid| 23.4224|
Mass of empty weighing bottle| 23.2883|
Mass of ascorbic acid (C6H8O6)| 00.1341|

Table 1: Titration of diluted ascorbic acid
Titration number:| Rough| 1| 2| 3| 4| |
Final diji reading/mL| 15.00| 33.70| 32.50| 14.60| 14.50| ±0.02| Initial diji reading/mL| 0.00| 19.20| 18.10| 0.00| 0.00| ±0.02| Titre / mL| 15.00| 14.50| 14.40| 14.60| 14.50| | Number of OK titres, N| | OK| OK| | OK| 3|

Sum of OK titres| | 14.50| 14.40| | 14.50| 43.4| Average/ mL| | | | | | 14.47|

Calculations:
Concentration of stock ascorbic acid
* Mols of ascorbic acid: 0.1341/176 = 7.619 *10^-4
* Concentration = (7.619 *10^-4) / 0.1 = 0.007619 mol/dm3 Concentration of diluted solution of ascorbic acid
* V1*M1 = V2*M2
* Concentration = (0.01 * 0.007619) / 0.1 = 7.619*10^-4 mol/dm3
Concentration of NBS
* Mols of diluted ascorbic acid: (7.619*10^-4) * 0.01 = 7.619*10^-6 mols * Mols of NBS = Mols of ascorbic acid = 7.619*10^-6 mols * Concentration of NBS: (7.619*10^-6) / 0.01447 = 5.265*10^-4 mols/dm3

Results: Table 2: titration of ribena
Titration number:| Rough| 1| 2| 3| |
Final diji reading/mL| 16.00| 15.80| 31.50| 15.80| ±0.02| Initial diji reading/mL| 0.00| 0.00| 15.80| 0.00| ±0.02| Titre / mL| 16.00| 15.80| 15.70| 15.80| |...

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