What was the molar concentration of acetic acid in the vinegar?

Analysis of Vinegar by titration?

• 5% wv acetic acid= 5 grams acetic acid 100mL vinegar a) The chemical formula for acetic acid is HC2H3O2. Determine the molar mass of acetic acid. b) Now convert the concentration of acetic acid in vinegar (5 grams acetic acid/100 mL vinegar) into Molarity units ( moles acetic acid/liter vinegar). How many mL of a 0.200 M NaOH solution are needed to react with a 5.00mL sample of vinegar that has the HC2H3O2 Morality determined in question 1

• Answer:

  a) To determine the molar mass, simply add the atomic weights of every atom in the compound. H = 1.008 C = 12.011 O = 15.999 (4 * 1.008) + (2 * 12.011) + (2 * 15.999) = 60.052 g/mol b) Simply convert grams to moles using the molar mass above, then divide by the number of liters (1 L = 1000 mL) 5 g acetic acid / 60.052 g/mol = 0.08 mol 0.08 mol / 0.1 L = 0.8 M The final part of this question is an acid/base titration; the equation we will use is: MaVa = MbVb Given: Ma = 0.8 M Va = 5.00 mL Mb = 0.200 M Solve for Vb: Vb = MaVa / Mb = 0.8 M * 5.00 mL / 0.200 M = 20 mL (Note that throughout, I have been using 1 significant figure in my answers, because the original problem's lowest number of significant figures was 1. If the original problem had said, for example, 5.0% w/v, 5.0 g, and 100. mL, you'd use 2 significant figures, and you'd get 0.83 M and 21 mL as your answers instead.)