Your report form for this experiment will include 3 attached Excel spreadsheets (each one on a separate 8.5”x11” sheet of paper). Each spreadsheet MUST INCLUDE (i) the titration data (ii) the titration curve graph and (iii) a data box.
science
Description
102 Exercise 7 Report Form: Acids
and Bases – Titration Curves (Part 1)
Your report form
for this experiment will include 3 attached Excel spreadsheets (each one on a
separate 8.5”x11” sheet of paper).
Each spreadsheet MUST INCLUDE (i) the titration data (ii) the titration
curve graph and (iii) a data box.
(3 points) For acetic acid:
(i) The titration curve data in two columns.
(ii) The graph of pH versus volume of titrant.
(iii) In the data box include the value of pKa
as determined from the pH halfway to the equivalence point and the molarity
of the acetic acid using 0.075 M NaOH for the titrant and the volume of
titrant used at the observed equivalence point.
An example is given below (note the values are examples only):
|
Data Box |
|
|
Equivalence
point (mL titrant) |
12.50 |
|
Half
equivalence point (mL titrant) |
6.25 |
|
Half
equivalence point pH |
4.34 |
|
pKa |
4.34 |
|
Original
molarity of acetic acid (mol/L) |
0.094 |
(3 points) For phosphoric acid:
(i) The titration curve data in two columns.
(ii) The
graph of pH versus volume of titrant.
(iii) In the data box include
the values of pKal and pKa2 as determined
from the pH halfway to the relevant equivalence points, and the molarity of
the phosphoric acid using 0.075 M NaOH for the titrant and the volume of
titrant used at the observed equivalence points. An example is given below (note the
values are examples only):
|
Data Box |
|
|
Equivalence
point 1 (mL titrant) |
10.00 |
|
Equivalence
point 2 (mL titrant) |
20.00 |
|
Half
equivalence point 1 pH |
4.89 |
|
Half
equivalence point 2 pH |
8.90 |
|
pKa1 |
4.89 |
|
pKa2 |
8.90 |
|
Molarity
of phosphoric acid (mol/L) |
0.082 |
(3 points) For the
unknown acid:
(i) The titration curve data in two columns.
(ii) The graph of pH versus volume of titrant.
(iii) In the data box include the value of pKa
for the weak acid, the molarity of the weak acid and your guess of the identity
of the weak acid. Possible unknown
weak acids from which to choose from are:
|
|
Ka |
|
Acetylsalicylic acid |
3.3x10-4 |
|
Lactic acid |
1.4x10-4 |
|
Benzoic acid |
6.5x10-5 |
|
Potassium hydrogen phthalate |
3.9x10-6 |
|
Hydrogen chromate ion |
3.0x10-7 |
|
Phenol |
1.3x10-10 |
Below is an example of the data box (note the values are
examples only):
|
Data Box |
|
|
Unknown
number |
1234 |
|
Equivalence
point (mL titrant) |
10.67 |
|
Original
molarity of the unknown acid (mol/L) |
0.103 |
|
Estimated
pKa |
6.54 |
|
Identity
of the unknown acid |
Phenol |
