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Introduction

Acid Content of Vinegar Aim: -To determine the concentration of ethanoic (acetic) acid in a sample of vinegar. Apparatus: As per prac sheet Method: As per prac sheet Safety: Results: Morrow Vinegar- Titration repeat Initial reading Final Reading Titre 1 2.45ml 31.59ml 29.14ml 2 4.01ml 33.52ml 29.51ml 3 4.32ml 34.02ml 29.70ml Aceto Vinegar- Titration repeat Initial reading Final Reading Titre 1 2.32ml 28.90ml 26.58ml 2 0.77ml 28.23ml 27.46ml 3 3.71ml 29.19ml 25.48ml Cornwalls Vinegar- Titration repeat Initial reading Final Reading Titre 1 3.35ml 23.41ml 20.06ml 2 4.13ml 24.80ml 20.67ml 3 3.65ml 24.31ml 20.66ml Questions: 1) Calculate the mass of ethanoic acid in each sample of vinegar. The mass of ethanoic acid in the sample of Morrow vinegar is: 0.1767g n(NaOH) = c � v = 0.1 � 0.02945 n = 0.002945 mol n(CH3COOH) = 0.002945 mol (n(NaOH) and n(CH3COOH) ...read more.

Middle

= c � v = 0.1 � 0.02046 n = 0.002046 mol n(CH3COOH) = 0.002046 mol m = n mr mass(CH3COOH) = 0.002046 � 60 = 0.12276 grams 2) Calculate the average concentration of ethanoic acid in the vinegar as a percentage by mass. The average concentration of ethanoic acid in the Morrow vinegar is 5.87 % w/w. c = amount of solute � 100 amount of solvent c = 0.1767 � 100 3.01 c = 5.87 % w/w The average concentration of ethanoic acid in the Aceto vinegar is 5.28 % w/w. c = 0.15906 � 100 3.013 c = 5.28 % w/w The average concentration of ethanoic acid in the Cornwalls vinegar is 4.06 % w/w. c = 0.12276 � 100 3.027 c = 4.06 % w/w 3) ...read more.

Conclusion

4.06 grams in 100 grams 375�100= 3.75 3.75�4.06= 15.225 grams of ethanoic acid in 375ml of Cornwalls vinegar 15.225 grams cost $1.79 1.79�15.225 = $0.11757 1 g = 11.76 cents 4) If different members of your class used different brands of vinegar, which brand appears to be the best value for money based on ethanoic acid content? Based on ethanoic acid content, Morrow vinegar appears to have the best value. Morrow is the cheapest, with 1 gram costing 7.56cents, Cornwalls is the second, with 1 gram costing 11.76 cents, and Aceto vinegar is the most expensive, with 1 gram costing 15.11 cents. 5) Write an equation for the reaction that occurs between the ethanoic acid and the sodium hydroxide. Ethanoic acid and sodium hydroxide react together to form products: sodium acetate and water. CH3COOH(aq) + NaOH (aq) CH3COONa(aq) + H2O(l) ...read more.

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