Question

Acid-Base Titration PRE-LABORATORY ASSIGNMENT This assignment must be completed in your notebook prior to attending pre-lab lecture. 1. Sketch a picture of a 50 mL buret. Clearly label the location on the 0.00 mL line and the 50.00 mL line on the buret. Refer to appendix 5E for information about a buret. 2. Write the balanced chemical equation that will be used during this titration experiment. 3. Assume a student performed the acid-base titration experiment that you will be doing in Expt. 8. The student accurately transferred 5.00 mL of vinegar into an Erlenmyer flask, added indicator, and performed the titration by adding sodium hydroxide. The student filled the buret with a 0.003 M NaOH solution and recorded an initial buret reading of 2.12 mL and final buret reading of 41.05 mL. Calculate the following values showing all work: a. Actual volume (mL) of NaOH solution used b. Moles of NaOH reacted during titration C. Moles of acetic acid reacted during titration d. Grams of acetic acid reacted e. Grams of vinegar solution used during titration f. Mass % of acetic acid in the vinegar: mass % = grams of acetic acid/ grams of vin- egar *100

Answer 1

50 mL burit @ CH3COOH(aq) + NaOH(aq) → CH3COONa (29) + HOU) op H*(aq) + oH (aq) → Hole) 4 40 @ volume of NaOH Solution used =Ve-V:) =(41:05-2012)m. = 38.93 mL Moles of Naoh reacted = 38.93 ml of 0.003 (M) = 138.9340.003) mol © Moles of acetic and reacted = moles of Naoh reacted = 1.1679x104 mol = 1.1679810 mot. @ Molar mass of acetic acid (CH3COOH) = 60.052 g/mol . Gerains of acetic and reached = 4:1679x104x60.0529 0529 = 7:0135 x 109 @ Grains of vinegar saution used – (5ml.xd g/ml) = 50 g In order to calculate the mass of vinegar used its Leusitých) [d= density of vinegar) must be supplied ® Massy of acetec ceed in vinegar = 17.0135*10*1001V 5d