Part 2: Titration Curves with Labquest1.From the sensor window tap mode and at the top of the screen select “Events with Entry”.2.Give the column a name like “Volume of NaOH added”. Enter theunits as mL. Go to the chart screen and you are ready to begin.Observation4. Calibration proved to be successful after testing these three buffer solutions and landing within their voltage reading ranges.
3.When you press the startbutton notice a small “keep” button appearsto the right of the start/stop button. Use the keep button every time you wish to record the pH. So place the pH probe in you acid solution press start and before titrating when the pHhas stabilized press KEEP. A window appears where you enter thevolume of NaOH added, in this case 0. Record the pH every 1-2 mL initially by pressing keep each time and entering the volume added. DO NOT PRESS STOPuntil the titration is completely over.4.When you do your second run be sure you save your 1strun.5.Export you data to a thumb drive to create the plots for your lab report.Part 3: Titration of a Strong Acid1.Place 25 mL (via volumetric pipet) of the HCl solution in a clean, labeled 100 mL beaker, and add a stirring bar and 1-2 drops of phenolphthalein.2.Obtain 75 mL of a 0.100 M NaOH solution in a clean, labeled beaker, record exact molarity.3.Fill a clean 50 mL buret with the NaOH solution, take initial reading to.01 mL.4.Place the acid beaker on a stirring plate and secure the pH electrode in the beaker.
5.Position the buret containing NaOH just inside the acid beaker, with the tip below the rim but above the solution surface.6.Turn stirring plate on to medium speed.7.Begin to slowly add 1 to 2 mL portions of NaOH solution to the acidbeaker, record the pH and corresponding buret reading on data sheet 1 and on the LabQuest.8.When pH readings begin to increase rapidly, add NaOH solution in 0.1-0.2mL increments.9.Watch for the change in color in the solution. The pink color will appear and fade. Best to try to watch for a fade pink color to remain. Record volume of titrant.10. When the pH reading reaches 9 you can add 1 to 2 mL portions of NaOH again.11. When you reach a pH of around 11 you are done.12. Press the stop button on the LabQuest and export the data to a thumb drive.13. Use the obtained data to calculate the concentration of the titrated acid (HCl).14. Use the calculated molarity value in experiment V.12. During this process, we started out with adding increments of 1 mL NaOH at a time and starting with an initial pH of 1.14. But soon after a few measurements, we switched over to adding increments of 2 mL NaOH at a time. When the pH gradually roseto about 2.17 after adding 20 mL NaOH, we slowed down by adding increments of 0.5 mL NaOH and eventually adding incrementsof only 0.1 mL NaOH. When we added about 25 mL NaOH to the solution, the pH reached the equilibrium point at 7.77 and then the solution turned completely pink after a couple more drops of NaOH. In the end, the pH reached 11.93 after about 32 mL NaOH was added.
Part 4: Titration of a Weak Acid1.Place 25 mL (via pipet) of Acetic acidsolution in a clean labeled 100 mL beaker. Add a stirring bar and
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- Spring '16
- Crystal Gambino