1. 4.6 DOUBLE DISPLACEMENT REACTIONS

2. Involves both elements in different compounds displacing each other or exchanging places.
The metals switch places and the non-metals switch places
Analogy - two couples dancing and they switch partners

3. The general equation for a double displacement reaction is:
AB + XY  AY + XB
Examples: Complete and Balance the reactions!
FeCl Na2S   
AgNO NaCl 
Pb(NO3) KI  `

4. Types of Double Displacement Reactions
1) Production of a Precipitate
A precipitate is an insoluble compound that forms when two clear liquids are mixed
Depends on the solubility of the chemicals involved
Chemicals with low solubility tend to form precipitates
Useful for removing harmful ions

5. Separating a precipitate:
A filtration apparatus is designed to separate a precipitate from a liquid.
The filtrate can be allowed to evaporate, revealing any more soluble compounds.

6. 3) The reaction in neutralized
2) Production of a gas
Gas is one of the products that is formed
3) The reaction in neutralized
Also called an acid base reaction
The products formed are neither acidic or basic
Products are usually water and a “salt” (ionic compound)

7. Solubility Solute: a substance that dissolves in a solvent
Solvent: the substance in which a solute will dissolve
Solubility: a property of a substance where the maximum amount of solute that will dissolve in a known quantity of solvent at a set temperature and pressure

8. if a chemical is very soluble it will stay in solution
if a chemical is not very soluble it will sometimes come out of solution in the form of a solid called a precipitate
the precipitate will get the subscript symbol (s) which stands for solid 
if a chemical in not very soluble it will sometimes come out of solution in the form of a gas
the gas will get the subscript symbol (g) which stands for gas

9. There is a solubility table on page 173 of your text
1. Find the anion part in column 2
2. look at column 2 and see if your cation part is in the list of exceptions
3. If you do have an exception, and it is in the soluble row, a precipitate WILL form
4. If you do have an exception, and it is in the insoluble row, NO precipitate will form

11. Examples! Ex. 1 Will potassium chloride precipitate out of solution?
Ex. 2 Will ammonium sulfate precipitate out of solutions?
Ex. 3 Will Barium sulfate precipitate out of solutions?

12. Ex. 4 Predict the products formed when calcium chloride and sodium carbonate are mixed.
Ex. 4 Predict the products formed when sodium sulfide solution and hydrochloric acid are placed in a beaker together.

13. For the following ions, determine what you could use to precipiate it out of a water sample.
A) Lead (II)
B) Mercury (I)
C) Copper (I)