Make A Buffer

Let's Make a Buffer

Instructor: Dr. Stone
Submit report to: turnitin.com
Points: 100
Due: April 3, 2015

The goals of this project:

1. Make a buffer
2. Write complete detailed (SOP, Standard Operating Procedure) instructions for making your buffer
3. Design an experiment to prove that you made the buffer
4. Design an experiment to show the buffering capacity (both acid and base) of your buffer
5. Write a lab report that includes the theory of buffers, your SOP, and details of the two experiments you designed (methods, data, results, conclusion.)

You may choose any chemicals for your buffer and you may choose any pH. Your buffer should be able to withstand both acid and base additions. The concentration of your buffer should be physiologically relevant. (Go to the literature and see what concentrations are used, be sure to cite the references you used.) You will submit a 50 mL sample of your final product (buffer solution) to Dr. Stone.

Calibration of pH electrode:
Always keep your pH electrode submerged in solution and be careful with it, as they are very fragile.
1. Open the microlab software by double clicking on the "Microlab" icon on the Desktop.
2. From the "Choose an Experiment" window, double click on "Microlab Experiment" icon.
3. From the "Data Sources" pulldown, select "Add a Sensor", and choose" pH/D.O." as the sensor.
4. Click on the red box surrounding the BNC cable input on the microlabunit picture.
5. In the "Choose a sensor" box, click pH and then click "Next".
6. In the "Calibration" window, click "Perform New Calibration".
7. In the "Calibrate a sensor" window, click "Add Calibration Point".
8. Rinse the pH electrode with DI water and submerge it in the pH = 4 buffer solution.
9. Once the reading has stabilized, enter 4 in the "Actual value" field and click OK.
10. In the "Calibrate a sensor" window, click "Add Calibration Point" again.
11. Rinse the pH electrode with DI water and submerge it in the pH = 7 buffer solution.
12. Once the reading has stabilized, enter 7 in the "Actual value" field and click OK.
13. Rinse the pH electrode with DI water and submerge it in the pH = 10buffer solution.
14. Once the reading has stabilized, enter 10 in the "Actual value" field and click OK.
15. Select "First Order (Linear)" from the "Curve Fit Choices" box, then click "Accept and Save this calibration" and click OK.
16. Save the file with a name specific the date of the lab such aspH_11_05_09", then click "Finish”.
17. Drag the pH sensor icon to empty box in the lower right of the micro lab screen to display the pH.

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