Answer Happy

Part A: Acetic acid/sodium acetate buffers 1. Using a graduated cylinder, a buffer solution is prepared from 20.0 mL of 0.10 M acetic acid and 30.0 mL of 0.10 sodium acetate. You will: a. Calculate the pH of the buffer. (Ka = 1.8 x 10-5) b. Compare a measured pH (given to you) to the calculated one. C. Compare the experimental result in (b) to the calculated value in (a) and determine the % error. 2. The buffer solution in (1) is divided into two equal 25.0 mL volumes. Calculate the expected pH of the following solutions and compare to the measured pH of each (given to you). a. To one of the 25.0 ml solutions, 5.0 mL of 0.10 M HCl is added. The measured pH is given. b. To the second 25.0 ml solution, 5.0 mL of 0.10 M NaOH is added. The measured pH is given. C. Calculate the theoretical pH for both a) and b) and compare the results with the measured pHs given to you. 3. Also calculate the expected pH of: a. Deionized water. b. Water after 5.0 mL of 0.10 M HCl is added to a 25.0 mL volume of water. c. Water after 5.0 mL of 0.10 M NaOH is added to a new 25.0 mL volume of water.
Buffer pH pH % pH theoretical experimental error theoretical Initially Initially after adding acid 4.92 рн % pH experimental error theoretical after adding after adding acid base 4.38 рн % experimental error after adding base 5.31 HC2H302/ C2H302 - H2O 7.12 2.05 12.45