Solubility The ability of an ionic compound to dissolve in water. The ability of an ionic compound to dissolve in water. A soluble compound disappears when mixed with water (aqueous) A soluble compound disappears when mixed with water (aqueous) Mixing kool-aid with water is soluble Mixing kool-aid with water is soluble An insoluble compound can still be seen when mixed with water An insoluble compound can still be seen when mixed with water Mixing sand with water is insoluble Mixing sand with water is insoluble

DOUBLE REPLACEMENT REACTIONS (PRECIPITATION) two compounds exchange positive ions. two compounds exchange positive ions. AB + XY  AY + XB Both reactants are ionic compounds in aqueous solution (aq). Both reactants are ionic compounds in aqueous solution (aq). NaCl + Pb(NO 3 ) 2  PbCl 2 + NaNO 3 The Na and Pb switch places The Na and Pb switch places

DOUBLE REPLACEMENT REACTIONS (PRECIPITATION) NaCl(aq) + Pb(NO 3 ) 2 (aq)  PbCl 2 (s) + NaNO 3 (aq) For a double replacement reaction to occur, the reactants must be aqueous and at least one product needs to be a solid, liquid, or gas For a double replacement reaction to occur, the reactants must be aqueous and at least one product needs to be a solid, liquid, or gas A solid (precipitate) is formed when a product is insoluble. A solid (precipitate) is formed when a product is insoluble. A gas bubbles out of solution. A gas bubbles out of solution. A molecular compound (such as water) is formed. A molecular compound (such as water) is formed.

DOUBLE REPLACEMENT REACTIONS (PRECIPITATION) NaCl(aq) + Pb(NO 3 ) 2 (aq)  PbCl 2 (s) + NaNO 3 (aq) How do we know if a compound is aq, s, l, g? How do we know if a compound is aq, s, l, g? We look it up on the periodic table or solubility table We look it up on the periodic table or solubility table Ionic compounds -- look up negative ion on solubility table Ionic compounds -- look up negative ion on solubility table Soluble on table – aqueous Soluble on table – aqueous Insoluble on table – solid Insoluble on table – solid Molecular compounds – generally liquid, like water Molecular compounds – generally liquid, like water

Label (s) or (aq): Ca(NO 3 ) 2 Ca(NO 3 ) 2 AgBr AgBr MgI 2 MgI 2 AgClO 3 Cu(C 2 H 3 O 2 ) 2 BaSO 4

Label (s) or (aq): Li 2 CO 3 Li 2 CO 3 CuCO 3 CuCO 3 (NH 4 ) 2 CrO 4 (NH 4 ) 2 CrO 4 Zn 3 (PO 4 ) 2 Zn 3 (PO 4 ) 2 PbSO 3 KSO 3 CaS Ca(OH) 2

ACID/BASE NEUTRALIZATION reactions between a strong acid and a strong base to produce a salt and water. reactions between a strong acid and a strong base to produce a salt and water. NaOH + HCl --> NaCl + H 2 O NaOH + HCl --> NaCl + H 2 O