MetathesisDouble Replacement

Reactions

Basics Exchange of anions Never a redox – no change in oxidation # Must have a driving force in order to go

to completion1) PPT2) Gas – H2S, CO2, SO2, or NH3

3) Molecular Species – H2O, weak species or nonelectrolyte

About those GasesH2S any S-2 + acid H2S + salt

CO2 any CO3-2 + acid CO2* + H2O* + salt

SO2 any SO3-2 + acid SO2* +H20* + salt

NH3 any NH4+1 salt + strong base NH3*+ HOH* + salt

MEMORIZE (*ask me)

These ARE NOT Molecular Species

Strong Acids – always ionizeHClO4, HClO3, HCl, HBr, HI, HNO3, H2SO4

Strong Bases – always dissociateGroup 1 and Ba, Sr, Ca

NH4OH doesn’t exist it is always NH3 + HOH

Soluble Salts – always dissociate into ions

These ARE Molecular SpeciesWeak Acids, Weak Bases and WATER

THEY DO NOT BREAK APART EVER!!!!

Neutralization Reaction – produces H2O

Strong Acid + Strong Base HOH + Salt

Anhydrides1. 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 oxideBase anhydride – base w/o H, metallic oxide

Acid anhydride + Base Salt + HOHCO2 + LiOH Li2CO3 + HOH

Has an intermediate step that occurs, but is not written

CO2 + H2O H2CO3

AnhydridesBasic anhydride + acid Salt + HOH

MgO + 2HCl MgCl2 + HOHIntermediate step occurs, but not written.

MgO + HOH Mg(OH)2

2. Acid Anhydride + Basic Anhydride Salt CO2(g) + K2O(s)

K2CO3(s)