March 17, 2010 Get a h/w page, Organization tree w/s,

and a solubility rules page Complete the Warm up at your table

(Single replacement and combustion) You will need paper and something to

write with Today we will be discussing:

“How do you recognize and represent chemical changes?”Homework:

Double Replacement W/S

Important Dates:4/2: Reaction Test

Double Replacement

Double Replacement Reactions: A reaction which involves the exchange of ions

between two compounds

AB + CD → AD + CB

Ca(OH)2(aq) + 2HCl(aq) → CaCl2(aq) + 2H2O(l) 2NaOH(aq) + CuCl2(aq) → 2NaCl(aq) +

Cu(OH)2(s)

Double Replacement Predicament

All in aqueous solutions!

3 types of Double Replacement reactions

Formation of precipitate

Formation of water

Formation of a product which decomposes into a gas

Formation of Precipitate Solubility rules!!!!! AB(aq) + CD(aq) → AD(aq) + CB(s)

NaCl(aq) + AgNO3(aq) → AgCl(s) + NaNO3(aq)

BaCl2(aq) + Na2SO4(aq) → ? BaCl2(aq) + Na2SO4(aq) → BaSO4(s) + 2NaCl(aq)

Na2SO4(aq) + CaCl2(aq) → ? Na2SO4(aq) + CaCl2(aq) → CaSO4(s) + NaCl(aq)

Formation of Water

Between Acids and Bases (H+/OH-) HX(aq) + YOH(aq) → XY(aq) + H2O(l)

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)

H2SO4(aq) + Mg(OH)2 → ? H2SO4(aq) + Mg(OH)2 → MgSO4(aq) + H2O(l)

H3PO4(aq) + KOH → ? H3PO4(aq) + KOH → K3PO4 + H2O(l)

Formation of a product which decomposes into a Gas

Three products will decompose into gasses: H2CO3 → CO2(g) + H2O(l) NH4OH → NH3(g) + H2O(l) H2SO3 → SO2(g) + H2O(l)

CaCO3(s) + HCl(aq) → H2CO3(aq) + CaCl2(aq)

NaOH(aq) + NH4Br(aq) → NaBr(aq) + NH4OH(aq)

H2CO3 → CO2(g) + H2O(l)

NH4OH → NH3(g) + H2O(l)

Miscellaneous

Some DR can create gases without decomposition of a product Not very common, but they do occur

HCl(aq) + FeS(s) → FeCl2(aq) + H2S(g)

NaCN(aq) + HCl(aq) → NaCl(aq) + HCN(g)

Double Replacement Reactions AsCl3(aq) + H2S(aq) → ?

2AsCl3(aq) + 3H2S(aq) → As2S3(s) + 6HCl(aq)

HCl(aq) + CaCO3(aq) → ? 2HCl(aq) + CaCO3(aq) → CO2(g) + CaCl2(aq) + H2O(l)

FeCl3(aq) + NaOH(aq) → ? FeCl3(aq) + 3NaOH(aq) → Fe(OH)3 + 3NaCl(aq)

H2SO4 + KOH → ? H2SO4 + 2KOH → 2H2O(l) + K2SO4(aq)

HNO3 + Ca(CN)2 →? 2HNO3 + Ca(CN)2 →2HCN + Ca(NO3)2