Answer Happy

Determination of Acetic Acid Concentration in Vinegar Using
Titration
ACTIVITY 1 A Titration of Vinegar with Sodium Hydroxide 1. Place the 10-ml graduated cylinder on the electronic balance. 2. Tare the balance. 3. Dispense - 5 mL of vinegar into the graduated cylinder with a plastic pipet 4. Record the exact mass of vinegar in Data Table 1. 5. Transfer the vinegar into the clean 25-ml Erlenmeyer flask. 6. Add 2 drops of phenolphthalein to the vinegar. Take photograph of flask as the start point of the titration. 7. Transfer approximately 10 mL of 1 M sodium hydroxide (NaOH) to the small cup. This solution will be used to fill the syringe. 8. Fill the syringe with 1 M NaOH solution. Try to minimize the amount of air in the syringe. 9. Record the initial volume of NaOH solution in the syringe to the nearest 0.1 mL in Data Table 1 for Vinegar Sample 1. Read the volume of the syringe at the edge of the plunger. 10. Place the flask containing the 5.0 mL of vinegar on the white sheet of paper. The white background will make the color change more noticeable. 11. Add NaOH from the syringe in 0.5-mL increments, swirling the flask between each addition until a color change persists for a few seconds after the addition of the NaOH. 12. Add NaOH dropwise from the syringe, with constant swirling, until a single drop of NaOH causes a color change that persists for a few seconds after the addition. This indicates that the end point has been reached. 13. Once the end point has been reached, record the final volume of NaOH in the syringe in Data Table 1 for Vinegar Sample 1 Take photograph of flask as the end point of the titration. 14. Calculate the total volume of NaOH that was required to reach the end point and record the data in Data Table 1. 15. Dispose of the titrated vinegar sample in the sink. 16. Rinse the 25-ml flask three times with water. 17. Repeat steps 1-16 for Vinegar columns 2 and 3 on the Data Table 1. 18. Calculate the concentration of acetic acid in your vinegar sample based on your experimental data The molar mass of acetic acid is 60.05 g/mol.
Activity 1 Data Table 1 Name of Vinegar Sample Vinegar Sample 1 Vinegar Sample 2 Vinegar Sample 3 Mass of Vinegar Volume of Vinegar Initial NaOH Volume in Syringe Final NaOH Volume in Syringe Volume NaOH Delivered Moles of NaOH Delivered
Name of Vinegar Sample Vinegar Sample 1 Vinegar Sample 2 Vinegar Sample 3 Moles of Acetic Acid in Sample Mass of Acetic Acid in Sample Calculated Molarity of Acetic Acid in Sample Vinegar Calculated Percent Mass of Acetic Acid in Sample Vinegar Average Calculated Percent Mass of Acetic Acid in Sample Vinegar
1. List 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? 2. Given the following experimental data, calculate the molarity of the acid analyte (HA) in the titration, if the balance neutralization reaction is: HA + NaOH → NaA + H2O. 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. 1 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.