1. Metathesis Double Replacement Reactions

2. Basics Exchange of anions Never a redox – no change in oxidation # Must have a driving force in order to go to completion 1) PPT 2) Gas – H 2 S, CO 2, SO 2, or NH 3 3) Molecular Species – H 2 O, weak species or nonelectrolyte

3. About those Gases H 2 S any S -2 + acid  H 2 S + salt CO 2 any CO 3 -2 + acid  CO 2 * + H 2 O* + salt SO 2 any SO 3 -2 + acid  SO 2 * +H 2 0* + salt NH 3 any NH 4 +1 salt + strong base  NH 3 *+ HOH* + salt MEMORIZE (*ask me)

4. These ARE NOT Molecular Species Strong Acids – always ionize HClO 4, HClO 3, HCl, HBr, HI, HNO 3, H 2 SO 4 Strong Bases – always dissociate Group 1 and Ba, Sr, Ca NH 4 OH doesn’t exist it is always NH 3 + HOH Soluble Salts – always dissociate into ions

5. These ARE Molecular Species Weak Acids, Weak Bases and WATER THEY DO NOT BREAK APART EVER!!!! Neutralization Reaction – produces H 2 O Strong Acid + Strong Base  HOH + Salt

6. Anhydrides 1. Watch for acid and base anhydrides that react with water before they react with the acid or base present. Acid anhydride – acid w/o H, nonmetallic oxide Base anhydride – base w/o H, metallic oxide Acid anhydride + Base  Salt + HOH CO 2 + LiOH  Li 2 CO 3 + HOH Has an intermediate step that occurs, but is not written CO 2 + H 2 O  H 2 CO 3

7. Anhydrides Basic anhydride + acid  Salt + HOH MgO + 2HCl  MgCl 2 + HOH Intermediate step occurs, but not written. MgO + HOH  Mg(OH) 2 2. Acid Anhydride + Basic Anhydride  Salt CO 2(g) + K 2 O (s)  K 2 CO 3(s)