CH 8 Solubility Rules & Net Ionic Equations

Chemical Reactions Many chemical reactions take place in solution. This means that the ionic compounds are dissolved in water. Many ionic compounds dissolve readily in water and form aqueous solutions. They are considered soluble. This is represented in a chemical reaction by placing (aq) after the formula for the salt. NaCl (aq) + AgNO 3(aq)  NaNO 3 (aq) + AgCl (s)

What is solubility? When a compound is soluble in water it will disassociate. When a compound disassociates, it breaks into its respective ions NaCl (s)  Na + (aq) + Cl - (aq) H2OH2O

What is Solubility? When a compound is insoluble in water, it remains a solid and does not disassociate. AgCl (s)  NR H2OH2O

Precipitate Reactions NaCl (aq) + AgNO 3(aq)  NaNO 3 (aq) + AgCl (s) Silver Chloride is the insoluble salt or precipitate formed in this reaction.

Precipitate Reactions Again, when two solutions are mixed and the result is an insoluble salt, a precipitate is formed

Solubility Rules We can predict if a solid will form as the result of a chemical reaction by using solubility rules. REMEMBER: Formation of a solid is one of the driving forces that indicates if a chemical reaction will take. place

Solubility Rules ALL nitrate, acetate and chlorate salts are soluble in water. ALL alkali metal and ammonium salts are soluble in water. Most chloride, bromide and iodide salts are soluble in water. EXCEPTIONS: Salts of Ag +, Pb +2/+4 Hg +2 Most sulfate salts are soluble in water. EXCEPTIONS: Salts of Ba +2, Ca +2, Pb +2/+4, Ag +, Hg +2, Sr +2

Solubility Rules Most hydroxide salts are insoluble in water. EXCEPTIONS: Rule #2 and salts of Ca +2, Ba +2, Sr +2 Sulfide salts are insoluble in water. EXCEPTIONS: Rule #2 and Group 2 metals. Chromate, carbonate, phosphate, oxygen, cyanide and thiocyanate salts are insoluble in water. EXCEPTION: Rule #2