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Experiment 10
Recovery of Silver Chloride
If you want to build a house, it would be difficult to simply pile all of the parts you need all together in
one mound and expect a habitable house to suddenly appear amongst it all. Just as you must first build
the foundation, then the walls, and finally the roof, some compounds must be prepared in a series of
steps, rather than all at once.

This concept is demonstrated in this laboratory, and it is controlled by an old friend – stoichiometry.

This lab will also familiarize you with the concept of molarity, an important way of measuring the
amount of solute in a solution.

SAFETY

Hydrochloric acid and sodium hydroxide are corrosive and will irritate or burn your skin. Silver nitrate
is an irritant (especially to eyes and mucus membranes) and will stain your skin (it turns black when
exposed to light). Always wear gloves, aprons, and goggles when working with these compounds.

BACKGROUND

In this lab, you will perform the stoichiometry calculations for two separate reactions, where one of the
products of the first reaction will become one of the reactants of the second. Your goal is to correctly
predict the yield of second reaction, then recover the insoluble product and determine your yield.

You will work largely without the guidance of the instructor during this activity. The stoichiometry is
calculations.

Solubility is a measure of the maximum amount of a compound that can be dissolved in a given volume
of water. The standard solubility in water of a compound is measured in g/100mL, and is generally
reported for water at 20°C.

The solubility of silver nitrate at 20°C is 216 g/100mL.
The solubility of hydrogen chloride at 20°C is 70 g/100mL.
The solubility of sodium hydroxide at 20°C is 109 g/100mL.

The concentration (strength) of a solution is reported in terms of molarity. The molarity of a solution is
measured in moles of solute (the substance being dissolved; in this lab acid, base, and salt) divided by
the total volume of the solution (in liters). Molarity is reported in mol/L.

Molarity  Total Volume ofofSolution (liters )
Moles solute

Experiment 10 – Recovery of Silver Chloride / 1
PRE-LAB ACTIVITY

1. Using the internet as a resource, write a short summary of the concept of molarity.

2. Use Google.com to look up “phenolphthalein.” What is its primary use? Its use is very important in
this experiment – explain why.

3. Use Google.com to look up “blue litmus paper.” What is its primary use? Its use is very important
in this experiment – explain why.

4. Use the information about molarity provided in the BACKGROUND section of this lab to
determine:
a. The number of grams of each compound dissolved in 1 liter of each of the solutions used in
this lab
b. The number of moles of each compound dissolved in one milliliter of each solution used in
this lab
c. The number of grams of each compound dissolved in one milliliter of each solution used in
this lab

5. Using the solubility data of the three compounds given above, determine the maximum molarity of
their solutions at 20°C.

MATERIALS

   3.0 M hydrochloric acid solution                        250 mL beakers
   2.0 M sodium hydroxide solution                         250 mL Erlenmeyer flask
   0.5 M silver nitrate solution                           Filter paper
   Phenolphthalein indicator                               Watch glass
   Blue litmus paper                                       Wash bottle
   Graduated cylinders                                     Deionized water

PROCEDURE

Any step marked with an asterisk (*) requires that you write or record some value or information. Be
very cognizant of this since you will need all of these values for your lab report.

Part One
The first portion of this lab requires you to perform an acid-base neutralization double replacement
reaction.
1. *Write a balanced equation for the neutralization. Write a total ionic and net ionic equation as well.
2. Obtain exactly 10 mL of the acid solution.
3. *Using information computed in the prelab activity, determine the mass of acid in 10 mL of the
solution.
4. *Once you know the mass of acid, calculate the mass of base is required to completely neutralize the
acid.
5. * Using information computed in the prelab activity, determine the volume of base solution that you
Experiment 10 – Recovery of Silver Chloride / 2
6. *Using the values gleaned from steps 2 or 3, determine the mass of soluble product that will be
generated as a result of this reaction.
7. Obtain the volume of base you calculated in step 5.
8. To the sample of base, add 5 drops of phenolphthalein indicator. Note the color of the base solution.
9. Slowly combine the 10 mL of acid solution and the base solution you obtained. Be aware of the
color change (if any) as the solutions are combined. Stir thoroughly.
10. Test the acidity of the solution with a piece of blue litmus. Use the very tip of the paper to avoid
soaking up any more solution than is absolutely necessary.

Part Two
The second portion of this lab requires you to perform another double-replacement reaction using the
soluble product from the acid-base neutralization. This reaction will be a precipitation reaction.

11. *Write a balanced equation for the reaction of the soluble product from part one with silver nitrate.
Write a total ionic and net ionic equation as well.
12. *Using the mass you calculated in step 6, determine the mass of silver nitrate required for this
reaction.
13. * Using information computed in the prelab activity, determine the volume of silver nitrate solution
that you will require for your reaction.
14. *Using the values gleaned from steps 6 or 10, determine the mass of insoluble product that will be
generated as a result of this reaction.
NOTE: Work quickly for the next two steps to avoid reaction of the silver nitrate with light in the
room.
15. Obtain the amount of silver nitrate solution you calculated in step 13.
16. Combine the products from your reaction in part one with the silver nitrate you obtained. Stir
thoroughly.

Part Three
The third portion of this lab requires that you recover your insoluble product and determine your percent

17. *Obtain a piece of filter paper and a watch glass. Write the names of your group members on the
edge of the filter paper, and determine the mass of both the paper and the watch glass.
18. Fold the blank piece of filter paper into a funnel and place it in the top of a 250 mL Erlenmeyer
19. SLOWLY pour your products from step 16 over the filter paper. Allow the liquid to drain through
the paper. The solid product will remain on the surface of the paper. If, after transferring all of the
liquid from your beaker, there is still solid in the beaker, you can use deionized water from a wash
bottle to help remove it.
20. Wash the solid several times with deionized water, to ensure that the soluble product has been
removed.
21. The liquid may take some time to flow through the product and filter paper. If time runs short, you
can place your flask in storage to allow it to trickle overnight.
22. Once all of the liquid has run through, carefully remove the filter paper funnel from your flask and
place it on a watch glass. Be sure to open the paper to allow for complete drying.
23. Place your product in storage to dry overnight, if it has not dried already.
24. *Once the product has dried, determine the mass, yield, and percent yield of your reaction.

NOTE: Your instructor must verify and initial your mass before you may wrap up.

Experiment 10 – Recovery of Silver Chloride / 3
CLEANUP AND DISPOSAL

Solid silver chloride should be disposed off in the collection container provided by your instructor. Acid
and base reaction waste (containing aqueous sodium nitrate) can be diluted with plenty of water and
washed down the drain.

DATA

Record the data from this lab in your notebook in any format you feel is appropriate. Remember, your
raw, handwritten data will be submitted with your lab report, so keep it neat and tidy!

POST-LAB ANALYSIS

Answer the following questions in complete, grammatically correct sentences (where appropriate).
When calculations are required, show all of your work.

1. Determine the percent yield of silver chloride in this experiment.

2. What is the soluble product in the second step of this experiment? Based on what you know about
the solubility of ionic compounds, is it feasible to conduct a further reaction with that product?
Explain why or why not.

3. Explain the purpose of the acid/base indicators used in this laboratory.

ONGOING LEARNING

Precipitation reactions are especially important in large-scale wastewater treatment processes. They are
most commonly used to remove phosphates, sulfur compounds, and undesirable heavy metals. The
resulting sludges are often difficult to handle and expensive to dispose of. However, the effectiveness of
the process and the relative compactness of the equipment make it more desirable than some of the
alternatives, such as activated biological removal.

Use the internet to learn what sorts of wastes are generated from residential wastewater treatment. Write
a few sentences summarizing the process you find, and a few more about how they are removed and
disposed of.

Experiment 10 – Recovery of Silver Chloride / 4

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