Pts during the addition of naoh in part b which

This preview shows page 11 - 14 out of 14 pages.

7.(3 pts) During the addition of NaOH in Part B, which buffer species reacted with theNaOH? Provide the balanced formula unit equation for this reaction.
PART B: Buffered Acetic Acid vs. NaOH(5 pts) Table 2: Relevant volumes and pH readings during the NaOHtitration of the buffer.
8.(3 pts) Based on the volume of NaOH added in Step 9 of the Data Analysis, determine thebuffering capacity of the buffered acetic acid solution. You may disregard the volume of“1 L” from the definition and refer to the volume used of the original buffer. Be sure toinclude the correct units.
Worksheet & Grading Rubric – Weak Acids and Buffersamount of moles in the NaOH in order to change the pH of the buffer solution by 1 pH unitwhich was 0.002180 moles (sample calculations made in Post Lab page 64).9.(6 pts) At volumes belowthe volume determined in Step 9 of the Data Analysis, discussthe relative changes in pH following subsequent NaOH additions. What happened to thepH following subsequent additions of NaOH afterthe Step 9 volume was reached? Why?Include the titration curve and second derivative curve from the Part BData Analysis.Figure 7: Titration Curve of Buffered acetic Figure 8:Second Derivative curve of PartBacid with NaOH.buffered acetic acid titration.At volumes below the buffering capacity, the relative changes in pH when titrations of 0.5mL increments were performed had a minimal increase. After the buffering capacityvolume was reached, the pH drastically increased and was due to how the weak acid couldno longer neutralize the strong base of NaOH (as the buffering capacity was reached), andexcess hydroxide ions were dissociated into the acetic acid solution, causing the pH of thesolution to drastically increase.PART C: Buffered Acetic Acid vs. HCl(5 pts) Table 3: Relevant volumes and pH readings during the HCltitration of the buffer.Titration ConditionsHCl added (mL)pHInitial 05.800Bufferingcapacityreached4.5334.800Equivalence point10.743.21712A. M. Bohnsack Spring 2019 (revised Z. Baranová)
Worksheet & Grading Rubric – Weak Acids and Buffers

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture