Basic Analytical Chemistry Laboratory
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SY 2020-2021
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Activity No. 3
GRAVIMETRIC DETERMINATION OF SULFUR IN A SOLUBLE SULFATE
DATA AND RESULTS:
Table 1. Constant weighing of crucible
No. of
Heating
Heating time,
minutes
Cooling time,
minutes
Example
I
Weight, g
II
1
60
15
III
21.4155
20.2028
19.7448
19.9798
2
30
15
21.4173
20.2065
19.7488
19.9825
3
30
15
21.4167
20.2074
19.7486
19.9824
4
30
15
21.4163
20.2070
5
30
15
Constant weight
21.4165
Table 2. Sulfate Sample
Example
I
II
III
weight of the container
45.6355
69.5876
69.3568
69.1255
weight of the container minus sample
45.3972
69.3568
69.1255
68.8938
gram sample
0.2383
gram S
0.02383
gram BaCl2
0.1548
mole BaCl2
0.0007433
mL of 0.1 M BaCl2
7.43
mL of 0.1 M BaCl2 + 20 mL excess
27.43
Table 3. Constant weighing of crucible plus precipitate
No. of
Heating
Heating time,
minutes
Cooling time,
minutes
Example
1
60
15
2
30
3
4
5
Constant weight
I
Weight,
g
II
III
21.7830
20.5398
20.0705
20.3100
15
21.7850
20.5418
20.0726
20.3123
30
15
21.7859
20.5416
20.0729
20.3127
30
15
21.7857
30
15
21.7858
Reference:
Capangpangan, Mario B., Quantitative Inorganic Analysis Laboratory Manual, Iligan City, Philippines,
(2004), pp. 9-10.
Basic Analytical Chemistry Laboratory
Table 4. Percent Sulfur in the Sample
Example
weight of crucible + precipitate
21.7858
weight of crucible
21.4165
weight of BaSO4
0.3693
weight of sample
0.2383
%S
21.29
I
II
III
STATISTICAL EVALUATION OF RESULTS
Mean, x
Median, M
Standard Deviation, s
Standard Deviation of the Mean, S
Relative Standard Deviation, % RSD
Reported Value
Reference:
Capangpangan, Mario B., Quantitative Inorganic Analysis Laboratory Manual, Iligan City, Philippines,
(2004), pp. 9-10.