3/6/2013 5:32:00 PM Part I Trial 1 Trial 2 Trial 3 50 50 50 30 35 20 30 26 38 Initial volume of NaOH in the buret Volume of HCI in the flask Volume of NaHO remaining at the end point Part II Trial 1 Trial 2 Trial 3 50 50 50 20 25 30 0.70 0.70 0.70 30 30 25 0.96 | 1.3 | 2.15 0.9 | 1.15 | 1.5 | 0.87 | 1.06 | 1.3 | 7.00 | 12.7 7.00 | 12.4 | 1.7 | 7.00 12.85 | 12.94 | 12.66 | 12.8 | 13 | 13.05 | 12.89 | 12.95 | 13.08 13 12.4 | 12.63 | 12.76 | 12.85 | 12.91 Initial volume of NaOH in the buret Volume of HCI in the flask pH when 0 mL of NaOH has been added Volume of NaHO remaining at the end point pH of solution each time an increment of 5 ml of NaOH is added. 5 | 10 | 15 | 20 | 25 pH of solution each time an increment of 5 ml of NaOH is added.30 | 35 | 40 | 45 | 50 Complete the following calculations for each part of the lab, showing your work neatly, labeling each calculation with a subtitle, and giving a brief written explanation of each calculation. 1. Determine the volume of sodium hydroxide added to the flask from the buret. 2. Calculate the molarity of the Hydrochloric acid in the flask. You may refer to the Titration demo at the beginning of the honors lesson, just above the Virtual Lab to see sample calculations. 3. Describe the graph of pH values over the course of the reaction in Part II. Was the change in pH consistent over the course of the reaction? Do your best to explain the reason for the shape of the pH curve in your own words. 4. Why is it important to stir the solution in the flask as you add titrant from the buret? 5. If a student did not remove all of the bubbles from inside the buret before reading the initial volume and beginning the titration, will this cause the calculated concentration of the hydrochloric acid determined from that trial to be higher or lower than the actual concentration? Explain your answer in complete sentences. 6. Describe at least three possible sources of error in a titration experiment like this and, for each, explain whether the error would result in a calculated molarity that is too high or too low.