Average Calculated Percent Mass of Acetic Acid in Sample VinegarList at least two possible sources of error from the experiment. Would these errors result in an overestimation or an underestimation of the concentration of acetic acid in the vinegar?
Activity 3 Data Table 3 Name of Sample Vinegar Vinegar Sample 1 Vinegar Sample 2 Vinegar Sample 3 Initial pH Reading pH = 3.211 pH = 3.102 pH = 3.105 Initial Buret Reading 2.89 mL 3.00 mL 1.61 mL Midpoint pH Reading pH = 4.895 pH = 4.687 Midpoint Buret Reading 12.92 mL 9.50 mL Final pH Reading pH = 8.238 pH = 8.531 pH = 8.934 Final Buret Reading 20.12 mL 20.31 mL 19.00 mL Volume of NaOH Dispensed Calculated Molarity of Acetic Acid in the Vinegar Sample Volume NaOH Dispensed at Midpoint Reading Moles of NaOH Consumed at Midpoint Reading [A–]
Moles of Acetic Acid Remaining at Midpoint [HA] Calculated p K a Average calculated molarity of acetic acid: Average acetic acid concentration expressed in percent by mass: Average value of p K a of acetic acid based on provided experimental data: Percent error for p K a of acetic acid: Given the following experimental data, calculate the molarity and the p K a of the acid analyte (HA) in the titration, if the balance neutralization reaction is: HA + NaOH NaA + H 2 O. A pH reading of 3.65 was obtained when 13.0 mL of 0.413 M NaOH was added to the 25.0 mL analyte. The endpoint was achieved when 31.25 mL of NaOH had been added. Photos Photo 1 Insert the photo of the 25-mL Erlenmeyer flask after the addition of phenolphthalein from Activity 1, step 6. Photo 2 Insert the photo of the 25-mL Erlenmeyer flask at the endpoint of the titration from Activity 1, step 13.
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- Fall '16