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Hi I have a lab report. the procedure was not given by the instructions/ instructor, so we I used an old procedure ( we had an option to make a research and find the procedure, but I used of of the last lab's procedure). you can look up a procedure for this lab. please follow all the striations provided below.
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DETERMINATION OF FREEZEG POINT OF ACETIC ACID, GLYCERIN AND ACETYLSALICILIC
ACID
Xxx
xxx
**/**/18
INTRODUCTION:
In the presented study the evaluation of freezing points of glacial acetic acid (HAc) as well as several
solutions of acetylsalicylic acid dissolved in glacial acetic acid was carried out. Additionally, one sample
of glycerin dissolved in glacial acetic acid was also tested. The analysis was carried out in two repetitions
in order to check the repeatability of the results. The solutions of acetylsalicylic acid dissolved in acetic
acid were prepared by dissolving the following amounts of acetylsalicylic acid ~0.05 g, ~0.10 g, ~0.15 g
into ~2 mL of acetic acid. This result will show how the freezing points, as well as freezing points
constant (Kf) change with the addition of solute into the solvent.
PROCEDURES AND OBSERVATIONS:
In order to determine freezing point of the selected solvent and solutions, different amounts of
acetylsalicylic acid were measured. Namely, ~ 0.05 g, ~ 0.10 g, ~ 0.15 g of previously mentioned acid was
measured in test tube. Then, in each test tube, 2.042 g (about 2 mL) of HAc was measured. Aslo, 4 g of
glycerin was measured in a separate test tube. The freezing point was determined following the procedure
described earlier1. The obtained results were used for Kf value determination.
Briefly, in the 8 inch test tube equipped with thermometer bulb 10 mL of adequate solvent (HAc) or
solution (glycerin or acetylsalicylic acid as a solute and HAc as a solvent) was added. The aperture was
placed in the cold water. During the process of cooling the solution was stirred until the formulation of
solid. Then, the solid mixture was removed from the cold water and the temperature had been followed for
some period in order to detect when the temperature does not change anymore. At that time the solution
reached the freezing point.
DATA
In table 1 are given the data obtained in this experiment. Also, the molar masses of glacial acetic acid
(C2H4O2), acetylsalicylic acid (C9H8O4) and glycerin (C3H8O3) were 60.052, 180.16, 92.09 g/mol,
respectively.
1
Table 1. The results obtained during the pKa determination for an unknown weak acid
Trial
Solution
1
1
1
2
2
2
1
2
3
1
2
3
Mass of
the test
tube +
HAc,
(g)
4.214
4.214
4.214
4.214
4.214
4.214
4.214
Mass of mass of
test tube HAc ,
+ HAc,
(g)
(g)
6.256
6.256
6.256
6.256
6.256
6.256
6.256
2.042
2.042
2.042
2.042
2.042
2.042
2.042
Mass of
aspirin,
(g)
No of
moles
aspirin,
(mol
TF
(°C)
mM,
(mol/kg)
Δ TF
(°C)
Kf,
(°C/ mM)
0.052
0.115
0.148
0.05
0.106
0.152
0.00028
0.00064
0.00082
0,00028
0.00058
0.00084
16.719
12.1...
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