Spreadsheet Assignment #1: Gravimetric Chloride Calculations and Report
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Gravimetric determination of chloride is accomplished by precipitation with
silver nitrate, followed by filtration and drying. Given the following data,
create a spreadsheet to calculate the percent chloride in each of the samples
below and to summarize the statistical data listed. Note that "Rep #"
refers to replicate number.
|
Sample ID: |
Rep # |
Sample Mass (g) |
AgCl Mass
(g) |
% Chloride |
|
98-J-32 |
1 |
0.2254 |
0.5295 |
. |
|
|
2 |
0.2104 |
0.4655 |
. |
|
|
3 |
0.2002 |
0.4226 |
. |
|
|
4 |
0.2342 |
0.5660 |
. |
|
|
5 |
0.2185 |
0.5282 |
. |
|
|
|
|
Average: |
|
|
|
|
|
Standard Dev: |
|
|
|
|
|
Relative Strd. Dev (%) |
|
Chemistry Helps:
Atomic Mass Cl: 35.4527
Atomic Mass Ag: 107.868
Recall that the % chloride is the grams of chloride divided by the total sample mass. To obtain the grams of chloride in a given quantity of AgCl the mass of AgCl is simply multiplied by the ratio of the atomic weight of the chlorine over the molar mass of the AgCl.
Programming Tips:
|
Excel
command: |
Result |
|
=AVERAGE(range)
|
Averages the numbers within the range |
|
=STDEV(range) |
Calculates the standard deviation of the numbers within the range. |
Dividing the standard deviation by the average returns the relative standard deviation. This is normally formatted in percent. Be sure to format your outputs with the correct number of significant figures.