Unit 4, Lesson 23

In a precipitation reaction, an aqueous solution reacts with a solution that isn't very soluble, and when combined, a solid product is formed. Precipitation reactions are double exchange reactions and their reactants are usually ionic compounds. Compounds that aren't very soluble will precipitate from aqueous solutions and show up in the product half of a chemical equation. There is a chart that says what compounds are soluble (represented by an 'S') and which compounds are not ('N'). Insoluble compounds are precipitates. There are precipitates in our own bodies: bones, teeth, and kidney stones. All three of these are made from some kind of calcium compound.

Problems: 

3.) Explain what a spectator ion is. A spectator ion is an ion that is noted in a chemical equation but doesn't exactly contribute to the equation itself. More, it just kind of floats around. Or, as Ms. McDowell would say, it "chills in the beaker" with the other compounds.

4.) Which ionic solids are soluble in water? (answers in bold)

LiNO3   KCl    MgCl2   Ca(OH)2   RbOH  

CaCO3  Li2CO3   PbCl2   AgCl