1. 3.4 Double Displacement Reactions

2. Double Displacement Reactions Double Displacement Reactions occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound Compound + compound  product + product AB + CD  AD + CB

3. Double Displacement Reactions Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together Example: AgNO 3(aq) + NaCl (s)  AgCl (s) + NaNO 3(aq) Another example: K 2 SO 4(aq) + Ba(NO 3 ) 2(aq)  KNO 3(aq) + BaSO 4(s) 2

4. Solubility of D.D. Products A property of a substance that describes it’s ability to dissolve in another substance at a given temperature and pressure The solute is the substance that is dissolved The solvent is the medium in which the solute dissolves If the product of a reaction is very soluble and will stay in solution it may be given the subscript (aq) A product that is insoluble is given the subscript (s) or (g) depending on it’s state when produced  A solid, undissolved product is a precipitate

5. Solubility Predictions Use Table 1 p. 173 to predict whether an ionic compound, formed as the product of a chemical redaction in solution, is likely to form a precipitate (not soluble) or form a solution (soluble) If both possible products are highly soluble, write “no reaction”

6. Practice Predict the products. Balance the equation 1. HCl (aq) + AgNO 3(aq)  2. CaCl 2(aq) + Na 3 PO 4(aq)  3. Pb(NO 3 ) 2(aq) + BaCl 2(aq)  4. FeCl 3(aq) + NaOH (aq)  5. H 2 SO 4(aq) + NaOH (aq)  6. KOH (aq) + CuSO 4(aq)  HNO 3(aq) + AgCl (s) Ca 3 (PO 4 ) 2(s) + 6NaCl (aq) 3 2 PbCl 2(s) + Ba(NO 3 ) 2 (aq) FeOH 3(s) + 3NaCl (aq) 3 H 2 O (l) + Na 2 SO 4 (aq) 2 Cu(OH) 2(s) + K 2 SO 4 (aq) 2

7. Types of Double Displacement Reactions Precipitate Reactions – one of the two products is an insoluble product  The other product may remain in solution  AgNO 3(aq) + KCl (aq) → AgCl (s) + KNO 3(aq) Reactions Producing a Gas – One of the products is a gas which is released  Na 2 S (aq) + 2HCl (aq) → 2NaCl (aq) + H 2 S (g)  See table 2 p. 176 for more examples of gases Neutralization Reaction – reaction between an acid and base where water and a salt (ionic compound) are produced  HCl (aq) + NaOH (aq) → NaCl (aq) + H 2 O (l)

8. Mixed Practice State the type, predict the products, and balance the following reactions: 1. BaCl 2 + H 2 SO 4  2. Zn + CuSO 4  3. Cs + Br 2  4. FeCO 3  2HCl + BaSO 4 D.D ZnSO 4 + CuS.D 2CsBr 3 32Synthesis Fe + CO 3 Decomposition

9. Homework Read pp. 172 – 177 Answer p.177 # 4 – 6