DRAFT: This module has unpublished changes.

Materials and Equipment:

  

- Data collection system                  - Ring stand

 - pH sensor                                   - Parafilm or aluminum foil

- Drop counter with micro stir bar      - Funnel

 - Magnetic stirrer                          - Hydrochloric acid, unknown concentration, 70 mL

- Buret, 50-mL                               - Sodium hydroxide (NaOH), standardized by

 - Graduated pipet with rubber bulb,      student in previous activity, 100 mL^2

   25-mL                                       - Buffers, pH 4 and pH 10, 10 mL

- Beaker, 100-mL (2)                      - Deionized water, 100 mL

- Beaker, 25-mL (2)                       - Wash bottle with deionized water

- Clamp, right-angle                       - Cotton swab or tissue    

- Clamp, buret

 

Methods:

 

1. Obtain about 20 mL 6 M HCL stock solution. Pipet 16.5 mL of the stock solution into a 1-L volumetric flask and fill the flack to the mark. Mix the content of the volumetric flask and transfer the solution into a 1-L plastic bottle. Label the bottle properly.

 

2. Start a new experiment on the data collection system.

 

3. Connect a pH sensor and the Rotary Motion sensor to data collection system.

 

4. In DataStudio create a calculated dataset for Volume.

  

5. In DataStudio create a calculated dataset for the first derivative of the pH vs. Volume. 

  

6. Display the pH on y-axis and Volume on x-axis.

 

7. Setup the Titrator pump.

 

8. Rinse the syringe on the Titrator pump.

 

9. Setup the Titrator Accessory.

 

10. Calibrate the pH sensor.

 

11. Add the micro stir bar to the end of the pH sensor.

 

12. Setup the titrant container and replace the cap on the bottle, but not airtight.

 

13. Load the syringe on the pump with the titrant solution.

 

14. Prime the pump on the Titrator. 

 

15. Use the graduated pipet to transfer 20.00 mL of the HCL solution into a 180 mL titration jar and mount the jar on the Titration Accessory over the magnetic stirrer. (In order to expedite the titration, while a sample is being titrated, prepare two additional samples for titration). 

 

16. Add enough deionized water to the solution so the tip of the pH sensor is covered with solution.

 

17. Turn on the magnetic stirrer at a steady rate.

 

18. Start recording data.

 

19. Press the "Run" button on the Titrator to start the titration.

 

20. Continue the titration past the equivalence point until the pH curve flattens.

 

21. Stop recording data.

 

22. Print the graph.

 

23. Save your experiment and clean up according to your teacher's instructions.

 

24. Clean the syringe in the Titrator.

DRAFT: This module has unpublished changes.