Question: CHM 152 Lab 9: pH Buffers Introduction In this lab you will prepare a buffer solution using acetic acid, HC H,O, and sodium acetate, NaCH,O, Last updated Aug. 2017 then compare its ability to resist pi changes with that of water Concepts to Review .Acid-base buffers Henderson-Hasselbach equation Solution pH Diluting solutions Procedure See Lab 08: Titration

CHM 152 Lab 9: pH Buffers Introduction In this lab you will prepare a buffer solution using acetic acid, HC H,O, and sodium acetate, NaCH,O, Last updated Aug. 2017 then compare its ability to resist pi changes with that of water Concepts to Review .Acid-base buffers Henderson-Hasselbach equation Solution pH Diluting solutions Procedure See Lab 08: Titration Curves for instructions on calibrating a pH meter. Mix 50.0 mL of 0.20 M sodium acetate with 10.0 mL. of 1.0 M acetic acid and 40.0 mL. deionized water. 1. Prepare a 50.0 mL burette as described in Lab 08: Titration Curves using 0.10 M HCI 2. Fill the burette with 0.10 M HCI to the 0.0 mL. mark 3. Fill a 250 mL. beaker with 50 mL. of your buffer solution. Measure the initial pH. 4. Add a total of 100 mL. HCI to the buffer, in increments outlined in the data sheet, recording the pH after each addition. Use the solution in the burette for the first 50 mL (do not drain past the 50 mL markt) Measure the final 50 mL with a graduated cylinder 5. Repeat steps 1-4 using deionized water instead of a buffer solution. Repeat Part II using 0.10 M NaOH in place of HCI. Part IV:Plotting the R You will input your data into Excel in three columns: voiune, ph tbutfer), and pH (water). Make sure the volume column is the first one listed so it's automatically set as the independent variable. Label each column in the first row of your spreadsheet 2. Input your data into from both Part I and IiI into a single table. To show pli changes in each tyne of solution (buffer and water) as one continuous curve, we're going to rig" our spreadsheet by listing the acid volumes as negarive numbers and the base volummes as positive humbers, making the range on our x-axis run from -100 to 100. For each set of data, only list a volume of 0.0 mL once (if the initial pH was different, use an average of the two as your pH at 0.0 mL) 3. To list the volumes in numerical order (-100 to 100), cli "Sort A to Z" buton (found in the Home tab, far right, under Sort & Filter) 4. Select all three columns (including the column headers) then plot the data as lines and markers. Label the x-axis-volume of acid (neg.) and base (pos) added, m ick on any cell in the volume column and use the a scatter plot with smooth Waste Disposal Solution waste can be poured slowly down the drain with running water .Rinse the pH probe with DI water and return it to the storage bottle. Rinse the burette three with approximately 20 mL of water, releasing some from the rinse out the tip (similar to what was done at the start of lab). Clamp your burets upside down at your station to dry stopper to