1. The Solubility Rules

2. Many Ionic Compounds are Soluble in Water
Water is a highly polar molecule, with strong dipoles
Ionic bonds are extremely strong, but many cannot withstand constant collisions with water molecules.
The solubility of ionic compounds varies with temperature.
Discounting temperature, however, there is a wide range of solubility for ionic compounds.

3. When sodium chloride is dissolved in water, to which end of the adjacent water molecules will a sodium ion be attracted?
the oxygen end, which is the negative pole
the oxygen end, which is the positive pole
the hydrogen end, which is the negative pole
the hydrogen end, which is the positive pole

4. Solubility Rules
There are a set of rules that chemists use to predict precipitates in double replacement reactions.
These rules are found on Table F; they have to be memorized in college classes

5. Note that Table F has much of the same information that Table E does:
The more common polyatomic ions are listed on Table F along with their formulas in a slightly more accessible form.

6. Let’s Look at the Solubility Rules
Some ions are always soluble, no matter what the counter ion is!
What is the important group 1 ion not mentioned here?
Why is seawater salty?

7. Some ions are more complex…
There are exceptions for halides and sulfates, which are generally soluble
Heavy metals are usually insoluble with everything but nitrate and acetate

8. Based on Reference Table F, which solution will contain the highest concentration of iodide ions?
lead iodide
silver iodide
mercury (II) iodide
iron (II) iodide

9. Ions that are usually insoluble:
Note that there are no truly insoluble compounds: tiny amounts of even the most insoluble compound do dissolve

10. What if there were no insoluble ions??
No fossils: no hard parts!
No shelled animals (CaCO3)
No vertebrates (you and me – Ca3PO4)
No heavy metal toxicity: sulfur binds these metals at extremely low concentrations…

11. Mercury Toxicity
Mercury is converted into highly toxic methyl mercury in soil by bacteria.
Symptoms of mercury poisoning include muscle weakness, poor coordination, numbness in the hands and feet, skin rashes, memory problems, trouble speaking, trouble hearing, or trouble seeing.
Symptoms depend upon the type, dose, method, and duration of exposure.

12. Minamata Disease
 High level exposure to methyl mercury is known as Minamata disease.
Mercury waste was dumped into a bay in Japan for 36 years.
Exposure in children may result in acrodynia (pink's disease) in which the skin becomes pink and peels.
Long term complications may include kidney problems and decreased intelligence.

13. Lead Toxicity
Lead poisoning is a type of metal poisoning caused by lead in the body.
The brain is the most sensitive.
Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, inability to have children, and tingling in the hands and feet.
It causes almost 10% of intellectual disability of otherwise unknown cause and can result in behavioral problems. Some of the effects are permanent.
In severe cases anemia, seizures, coma, or death may occur.

14. Lead Poisoning
In 2013 lead is believed to have resulted in 853,000 deaths. It occurs most commonly in the developing world.
Those who are poor are at greater risk. Lead is believed to result in 0.6% of the world's disease burden.
People have been mining and using lead for thousands of years.
Descriptions of lead poisoning date to at least 2000 BC, while efforts to limit lead's use date back to at least the 1500s.
Concerns for low levels of exposure begin in the1970s
There is no safe threshold for lead exposure.

15. Exceptions to Insolubility
Most, but not all exceptions are found on the other side of the table (Group 1, ammonium ion)

16. Fracking

18. Fracking Fluid
Millions of gallons of water and other chemicals are used to liberate methane from shale deposits.
Fracking fluid is basic: it contains lots of OH- ions.
Much of it has to be removed from the ground for reprocessing: it is 1000x more radioactive when it comes back up!

21. Why so much radiation?!?
Exposing rock to strong base liberates radium – a very radioactive decay product of uranium.
Ra(OH)2 is much more soluble than Mg(OH)2 (milk of magnesia)

22. Using Table F, determine which of the following are soluble/insoluble.
Compound
Soluble
Insoluble
Na2SO4
Mg3( PO4)2
BaSO4
SrSO4
KClO3
K2S
NH4NO3
Ba(OH)2
LiOH
(NH4)2CrO4

23. Compound
Soluble/Insoluble
Pb(ClO4)2
ZnS
KC2H3O2
(NH4)2SO4
K2CrO4
Co(OH)2
HgCO3
Hg2Cl2
NiCl2
NaC2H3O2

24. According to Reference Table F, which of the following compounds will form a saturated solution that is most dilute?
ammonium chloride
calcium carbonate
potassium iodide
sodium nitrate

25. Solubility Rules and Double Replacement Reactions
Assign oxidation numbers to each element, and find the charges of each polyatomic ion using table E.
Write the ion combinations and their charges on the product side.
Criss cross each charge to get the formula.
Balance each equation.
Determine the preciptate using Table F.
For those that should have precipitates, indicate which product is the precipitate by using a down arrow↓ or (s).

26. 1 2 3 No. Reactants Balanced Equation
Reactants
Precipitate Color
Balanced Equation 1
Sodium chloride and silver nitrate
Solubility rule: 2
cobalt (II) chloride and silver nitrate 3
sodium carbonate and silver nitrate

27. 4 5 6 potassium iodide and silver nitrate
potassium iodide and silver nitrate
Solubility rule: 5
lead (II) nitrate and ammonium hydroxide 6
lead (II) nitrate and sodium chloride

28. 7 8 9 lead (II) nitrate and potassium iodide
lead (II) nitrate and potassium iodide
Solubility rule: 8
copper (II) sulfate and sodium carbonate 9
copper (II) sulfate and ammonium hydroxide

29. 10 11 12 copper (II) sulfate and lead nitrate
copper (II) sulfate and lead nitrate
Solubility rule: 11
cobalt (II) chloride and sodium carbonate 12
cobalt (II) chloride and ammonium hydroxide

30. ZnCl2 + Na2CO3 →

31. CaCl2 + Pb(NO3)2 →
FeBr2 + K2CrO4 →

32. AlCl3 + Ba(OH)2 →
ZnCl2 + AgNO3 →
KI + Pb(NO3)2 →
KI + Ba(OH)2 →

34. Lab 22: Double Replacement Reactions and Solubility Rules
Objective
To study various double replacement reactions, identifying precipitates and spectator ions.
Introduction
Combining solutions of soluble ionic compounds often results in a product that precipitates.
The insoluble product can be determined by using the rules of solubility shown on Table F of your reference tables.

35. Materials Well plate, dropper bottles containing the following:
Sodium chloride, ammonium hydroxide, silver nitrate, sodium carbonate, potassium iodide, copper sulfate, cobalt chloride, lead nitrate; chemistry reference table.

36. Procedure
Take a well plate and clean it completely. Place 1 drop of the following in a well.
Be sure not to mix any of the chemicals accidentally!
To avoid this, do not put the dropper directly on the plastic well – drop the drop a half an inch above the well plate!

37. No.
Reactants
Reactant 1 Formula
Reactant 2 Formula
Precipitate Color 1
Sodium chloride and silver nitrate 2
cobalt (II) chloride and silver nitrate 3
sodium carbonate and silver nitrate 4
potassium iodide and silver nitrate 5
lead (II) nitrate and ammonium hydroxide 6
lead (II) nitrate and sodium chloride 7
lead (II) nitrate and potassium iodide 8
copper (II) sulfate and sodium carbonate 9
copper (II) sulfate and ammonium hydroxide 10
copper (II) sulfate and lead nitrate 11
cobalt (II) chloride and sodium carbonate 12
cobalt (II) chloride and ammonium hydroxide

38. Summary of Results
Using Table F, identify the precipitate and give two justifications based on the table. The first one is done for you.
No.
Precipitate
Justification #1 (soluble product)
Justification #2 (insoluble product) 1
Silver Chloride
Sodium is always soluble (Group 1); Nitrate is always soluble
Silver is insoluble with halides 2 3

39. No.
Precipitate
Justification #1 (soluble product)
Justification #2 (insoluble product)

40. Questions What are some possible sources of error in this experiment?
One student looked at a precipitate and identified the precipitate as pink. Her lab partner insisted it was white. Sometimes it isn’t easy to tell what the color of a precipitate is. Devise a method to find out!
Why do some combinations of solutions not produce precipitates?

41. Reactant Names
Sodium chloride and silver nitrate
Oxidation #s
Chemical Equation
cobalt (II)chloride and silver nitrate
sodium carbonate and silver nitrate

42. Results
Writing a balanced chemical equation is not that easy. There are a number of simple steps that you must take. The key is figuring out the formulas of the products.
Write the oxidation numbers of the elements over the chemical formulas of the reactants. Do the same for the charges on the polyatomic ions – use tables E and/or for this.
Draw the arrow to the products, and switch partners – the metal ion of one compound goes with the non metal ion or polyatomic ion of the other compound.

43. Try some new combinations!
Choose a combination of any two solutions that are not combined above. Describe what happens (or doesn’t happen) below:
There is at least one other combination that produces a precipitate. Use your reference tables to figure out what it is for extra credit!

44. Write the charges on the product side – they do not change in double replacement reactions!
Using the criss-cross method, determine the chemical formula of the products.
Use parenthesis when you have more than one polyatomic ion. Check with the teacher if you’re not sure.
Balance the equations using coefficients.
Determine the identity of the precipitate using Table F. Write a downward arrow ↓ or (s) after the chemical formula of the precipitate.

45. Reactant Names
potassium iodide and silver nitrate
Oxidation #s
Chemical Equation
Lead (II) nitrate and ammonium hydroxide
Lead (II) nitrate and sodium chloride
Lead (II) nitrate and potassium iodide
Copper (II) sulfate and sodium carbonate

46. Reactant Names
copper (II) sulfate and ammonium hydroxide
Oxidation #s
Chemical Equation
copper (II)sulfate and lead (II) nitrate
cobalt (II) chloride and sodium carbonate
cobalt (II)chloride and ammonium hydroxide