Jonah Chevrier
Nick Jiang
Ushhud Khalid
Philip Van-Lane
Introduction
Gravimetric Analysis is used to determine the
amount of a substance
 Stoichiometry is the study of the relationships
between products and reactants
 Gravimetric stoichiometry is the combination
of gravimetric analysis and stoichiometry
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Objective
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Approximate the amount of Cl- ions in AgCl
AgNO3 (aq) + NaCl(aq)  AgCl(s) + NaNO3(aq)
Dealing with limiting and excess reagents
 Filter out the AgCl from the NaNO3
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Materials
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Safety Goggles
Distilled Water
NaCl (0.117g) and AgNO3(aq)
Beaker
Erlenmeyer Flask
Dropper
Funnel
1 piece of (Whatman) filter paper
Porcelain crucible and lid
Crucible tongs
Ring clamp
Retort stand
Clay triangle
Bunsen burner
Accurate scale
Procedure
1. Measured mass of
empty crucible
2. NaCl solution created
3. Small amounts of
AgNO3 added
4. AgCl filtered using
filter paper and
funnel
Procedure Part 2
5. After the filter
paper had dried, it
was carefully
placed in the
crucible
6. Filter was allowed
to burn; AgCl
remained in the
crucible
7. Found mass of AgCl
Safety Precautions
Safety goggles
were worn at all
times
 Workspace was
free of clutter
 All hot materials
were handled with
care
 All substances
were handled
properly

Observations – Qualitative
• NaCl and AgNO3 were clear, aqueous
solutions
• Precipitate of AgCl formed from a double
displacement reaction
• Black substances remain; carbon from
filter paper which had not totally
dissipated
Observations – Qualitative
Observations – Quantitative
Objects Weighed
Mass (g)
Mass of empty crucible
10
Mass of crucible and lid
15.871
Mass of crucible and NaCl
10.117
Mass of crucible, NaCl, and lid
15.988
Mass of NaCl
0.117
Mass of crucible and AgCl
10.3191
Mass of AgCl
0.3191
Calculations
n = _ Mass _
Molar Mass
Theoretical: 0.002 moles
Actual: 0.002226475 moles
n = Number of molecules
NA
Theoretical: 1.2044 * 1021 molecules
Actual: 1.3407843432 * 1021 molecules
Calculations Part 2
Percentage Yield
| Actual / Theoretical | *100
=111.32%
Percentage of Error
| (Theoretical – Actual) / Theoretical | *100
=11.32%
Discussion
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Initial problem was to
separate AgCl(s) from the
NaNO3(aq)
 Both have very high boiling
points; evaporation would
not be feasible

Gravimetric analysis was
used for convenience
Discussion Part 2: Analytical Chemistry
Study of chemical composition of natural and
artificial materials
 Deals with 3 main questions

 What chemicals are present?
 Characteristics of the chemicals?
 Quantity of the chemicals?

Quantitative
 Amount of chemicals

Qualititative
 Determining presence of chemicals
Analytical Chemistry Part 2
Much focus on it between
the 17th and 20th centuries
 First kind of instrumental
analysis flame emissive
spectrometry

 Robert Bunsen, 1860
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Most studied branch of
chemistry
Discussion Part 3: Thermogravimetric Analysis
Part of instrumental analysis branch
 Study of weight changes in relation to
temperature
 Used to determine characteristics of
polymers
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 Large molecules composed of repeating structural
units
Discussion Part 4: Volumetric Titration
Another traditional
analytical technique
 Reagent of known
concentration and volume

 Titrant

Solution of unknown volume
and concentration
 Titrand
Volumetric Titration Part 2
Volume, instead of mass, is measured
 Titrant is added to titrand until endpoint is
reached

 Indicators make endpoint obvious to observers

Most often used for neutralization reactions
 Acid + Base  Water + Ionic Salt
Conclusion

Precipitate of AgCl formed through double
displacement reaction
AgNO3 (aq) + NaCl(aq)  AgCl(s) + NaNO3(aq)

0.3191g of AgCl
 1.3407843432 * 1021 Cl- ions in precipitate

Carbon particles remained
 Added to mass
Sources of Error
Inconsistence balance readings
 Contamination of chemical substances
 Uncertain if the Cl- ions had completely reacted
with the Ag+ ions
 Qualitative filter paper did not disintegrate
 Residue left in crucible from previous experiments
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Suggested Modifications
Use of quantitative filter paper rather than
qualitative
 More accurate balances
 Using materials which may not have been
contaminated from previous experiments
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