Volumetric flasks Beakers Serologic pipetters Aspirators Vials/test tubes Cone. H3PO4 (85% w/w, sp gr. 1.70, MM 98) Cone. HCL (37.3% w/w sp. Gr. 1.18, MM 36) Glacial acetic acid (99.7% ww, sp gr. 1.05, MM 60) NaOH pellets NaH2PO4 Na2HPO4 Acid-base indicators: Bromophenol Blue Bromocresol green Phenol red Methyl red Methyl orange Phenolphthalein Thymol Blue pH paper pH meter Weighing balance For chemicals, refer from the template below. Research the chemicals to be used especially those that are new to you and write down the information needed. Name of Chemical Molec. Weight (g/mol) Melting point Boiling point Density (g/mL) General properties Methodolody: (Include a short summary of the overall experimental plan you are going to run. You may use flow chart or bullet form for this part. Sketches of any experimental set-ups used in the experiment or the workup procedures). Preparation of buffers Prepare 250ml of the following buffer solutions. Concentration Buffer solution pka Desired ph 1 0.50 M Phosphate 2.12 2.0 2 0.50 M Phosphate 2.12 3.0 3 0.50 M Acetate 4.70 5.0 4 0.50 M Phosphate 7.21 7.0 5 0.050 M Phosphate 7.21 7.50 6 0.010 M Phosphate 7.21 8.0 7 0.50 M Phosphate 12.32 12.0 Identify the waek acid and conjugate base of the components of each buffer. Compute the buffer components using the Henderson-Hasselbalch equation. Preparation of reagents Prepare 500 ml of the following aqueous solutions. 0 M HCL 0M NaOH Determination of buffer capacity Calibrate the pH meter @ pH 4, 7 and 10. Prepare 100 ml each of 0.1 M HCL and 0.1 M NaOH. Using assigned buffer determine the buffer capacity by adding 0.1 M HCl in 1 ml portions from a buret to a 20 ml of the buffer until its pH changes as monitored with a pH meter. Record the columen added. Repeat this step using 0.1 M NaOH instead
Materials/Chemicals:
Volumetric flasks
Beakers
Serologic pipetters
Aspirators
Vials/test tubes
Cone. H3PO4 (85% w/w, sp gr. 1.70, MM 98)
Cone. HCL (37.3% w/w sp. Gr. 1.18, MM 36)
Glacial acetic acid (99.7% ww, sp gr. 1.05, MM 60)
NaOH pellets
NaH2PO4
Na2HPO4
Acid-base indicators:
Bromophenol Blue
Bromocresol green
Phenol red
Methyl red
Methyl orange
Phenolphthalein
Thymol Blue
pH paper
pH meter
Weighing balance
For chemicals, refer from the template below. Research the chemicals to be used especially those that are new to you and write down the information needed.
|
Name of Chemical |
Molec. Weight (g/mol) |
Melting point |
Boiling point |
Density (g/mL) |
General properties |
|
|
|
|
|
|
|
Methodolody: (Include a short summary of the overall experimental plan you are going to run. You may use flow chart or bullet form for this part. Sketches of any experimental set-ups used in the experiment or the workup procedures).
Preparation of buffers
- Prepare 250ml of the following buffer solutions.
|
|
Concentration |
Buffer solution |
pka |
Desired ph |
|
1 |
0.50 M |
Phosphate |
2.12 |
2.0 |
|
2 |
0.50 M |
Phosphate |
2.12 |
3.0 |
|
3 |
0.50 M |
Acetate |
4.70 |
5.0 |
|
4 |
0.50 M |
Phosphate |
7.21 |
7.0 |
|
5 |
0.050 M |
Phosphate |
7.21 |
7.50 |
|
6 |
0.010 M |
Phosphate |
7.21 |
8.0 |
|
7 |
0.50 M |
Phosphate |
12.32 |
12.0 |
Identify the waek acid and conjugate base of the components of each buffer. Compute the buffer components using the Henderson-Hasselbalch equation.
Preparation of reagents
- Prepare 500 ml of the following aqueous solutions.
- 0 M HCL
- 0M NaOH
Determination of buffer capacity
- Calibrate the pH meter @ pH 4, 7 and 10.
- Prepare 100 ml each of 0.1 M HCL and 0.1 M NaOH.
- Using assigned buffer determine the buffer capacity by adding 0.1 M HCl in 1 ml portions from a buret to a 20 ml of the buffer until its pH changes as monitored with a pH meter. Record the columen added. Repeat this step using 0.1 M NaOH instead.
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