Patterns in Solubility
Purposes: To explore factors affecting solubility
To make some generalizations regarding which compounds are soluble and
insoluble
To examine published solubility rules and compare these rules to your
generalizations
To gain preliminary practice writing some formulas of different compounds
Pre-lab Info: What does (aq) and (s) mean?
Basic Formula Writing (Common Multiple Method). What is a double replacement reaction?
Materials: Spot plates, 0.10 M solutions of the following compounds:
K2SO4,; BaCl2; NaOH; Hg2(NO3)2; Na2CO3; CuCl2; Pb(NO3)2,; Na2S; Na3PO4
Procedure: Prepare a data table as shown below. In the left margin try to predict which of these reactions will result
in the formation of a precipitate (Hint: there are 5).
Then in the lab, mix 2 – 3 drops of each solution in the combinations shown below. Allow 30 seconds for the reaction
to take place. Observe whether or not a reaction takes place. Note the color of any precipitate that does form. If no
reaction takes place, write “NR.”
REACTANTS
Na3PO4 (aq)
Pb(NO3)2 (aq)
Hg2(NO3)2 (aq)
Na2CO3 (aq)
NaOH (aq)
BaCl2 (aq)
NaOH (aq)
Hg2(NO3)2 (aq)
BaCl2 (aq)
+
+
+
+
+
+
+
+
+
K2SO4 (aq)
Na3PO4 (aq)
Na2S (aq)
K2SO4 (aq)
CuCl2 (aq)
K2SO4 (aq)
K2SO4 (aq)
Na3PO4 (aq)
CuCl2 (aq)
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






PRODUCTS
DATA

Data: Make an appropriate data table to record results. Allow 2-3 lines per reaction. Make sure to leave room for
writing the formulas of the products as well as data, as shown above.
Questions: Use Complete Sentences when appropriate.
1. Write all possible formulas for all products in your data section. Use the common multiple method to determine
these formulas. With another lab group, compare formulas and observations, checking to make sure you have
written the same formulas and data.
2. Now, look closely at your data. Look for recognizable patterns, and do your best to determine which products are
soluble and which products are insoluble. Wirte (aq) after any written formula which you think is soluble. Write
(s) after any written formula which you think is insoluble. Hint: when a ppt did form, one of the formulas written
is the ppt while the other is soluble. Put a “?” next to any compound you still aren’t sure about.
3. Look closely at your work from #2. What generalizations can you make regarding the soluble compounds? What
generalizations can you make regarding the insoluble compounds? How do you think the lattice energy of
insoluble ionic compounds compares to the lattice energy of soluble ionic compounds? Explain
4. After receiving the solubility rules chart, check to see that your work in #2 and 3 is correct, and to clarify any
questions you had. Make any necessary corrections. Also, check to see that the generalizations you made in #3
are accurate. Make any necessary corrections and additions.
Conclusion: WRITE A CONCLUSION SUMMARIZING YOUR DISCOVERIES
PLEASE INCLUDE THE FOLLOWING SECTIONS (FROM GUIDELINES) FOR YOUR LAB REPORT:
1,2,3,4,5&6 (attach handout),7,10,12